Ivar Sønbø Kristiansen

• Holly, Teresa; Brun, Marthe Kirkesæther; Jørgensen, Kristin Kaasen; Goll, Guro Løvik; Sexton, Joseph & Gehin, Johanna [Show all 15 contributors for this article] (2026). Cost-effectiveness of proactive therapeutic drug monitoring of maintenance infliximab treatment in patients with immune-mediated inflammatory diseases: results from a randomised controlled trial. RMD Open. 12(1), p. 11–11. doi: 10.1136/rmdopen-2025-006329. Full text in Research Archive Show summary

  Objective: Proactive therapeutic drug monitoring (pTDM) intends to optimise tumour necrosis factor (TNF) inhibitor treatment through regular assessment of drug and antidrug antibody levels, enabling individualised dosing. However, health economic evidence for this strategy is limited. This study aims to evaluate the health benefits and costs of pTDM with infliximab compared with standard therapy. Methods: Based on the 52-week randomised, controlled, open-label, multicentre Norwegian Drug Monitoring trial (NOR-DRUM) B trial, we estimated the cost-effectiveness of pTDM compared with standard infliximab maintenance therapy in patients with six different immune-mediated inflammatory diseases. For each patient (n=454), we estimated the 12-month healthcare costs, including pharmaceuticals, biochemical tests and other types of resource use. Reported in 2024 Euros, unit costs were based on market prices, diagnosis-related group cost weights and reimbursement schedules. We evaluated health outcomes with quality-adjusted life-years (QALYs), using the EuroQol five-dimension, three-level questionnaire (EQ-5D-3L) and Short Form six-dimension health utility measure (SF-6D). Indicator of cost-effectiveness was the incremental cost-effectiveness ratio, expressed as Euros/QALY, compared with an assumed cost-effectiveness threshold value of €23 755. We assessed sampling uncertainty using the non-parametric bootstrap. Results: The mean 1-year cost per patient in the pTDM group was lower than in the standard therapy group, with a difference of €592 (95% CI −1304 to 107), while the QALYs based on EQ-5D-3L were 0.0018 higher (95% CI −0.0126 to 0.0165). Based on the bootstrap results, pTDM has a probability of 95% of being cost-effective. In explorative subgroup analyses, pTDM appeared cost-effective for some, but not all diagnoses. Conclusion: pTDM is very likely a cost-effective treatment strategy for patients with immune-mediated inflammatory diseases on infliximab maintenance therapy.

• Wisløff, Torbjørn; Mundal, Liv Jorunn; Igland, Jannicke; Svendsen, Karianne; Bogsrud, Martin Prøven & Kristiansen, Ivar Sønbø [Show all 7 contributors for this article] (2025). Ten-year costs of cardiovascular disease in genetically verified familial hypercholesterolaemia compared with age- and sex-matched controls. European Journal of Preventive Cardiology (EJPC). ISSN 2047-4873. doi: 10.1093/eurjpc/zwaf592. Full text in Research Archive Show summary

  Aims Available data on economic consequences of carrying an inherited familial hypercholesterolaemia (FH) genetic variant are sparse. This study aims to explore the hospital and pharmaceutical resource use and costs associated with cardiovascular disease (CVD) in patients with genetically verified FH compared with age- and sex-matched controls during the period 2010 through 2019. Methods and results We included 5585 individuals with genetically verified FH from the Norwegian Unit for Cardiac and Cardiovascular Genetics registry and 111 483 age- and sex-matched controls from the general Norwegian population. Resource use and costs associated with CVD were collected from the Norwegian Patient Registry, the Cause of Death Registry, and the Norwegian Prescription Database. We estimated costs in European euros (EUR, €) based on diagnosis-related group (DRG) cost weights and pharmaceutical drug prices (Norwegian kroner 1 = EUR 0.1015). During 2010–19, patients with FH had CVD-related costs of €3911 per person for hospital care and €6119 for pharmaceuticals compared with €1498 and €514 among controls, respectively. The 10-year costs per person of percutaneous coronary interventions were €561 for FH and €140 for controls. The costs of CVD prescription drugs doubled in the FH population during 2010–19, largely due to the introduction of proprotein convertase subtilisin/kexin Type 9 inhibitors. Costs for prescription drugs increased in both the FH and control populations (P = 0.002 for FH and P = 0.005 for controls), while costs decreased for hospital care (P = 0. 0069 for FH and P = 0. 0943 for controls). Conclusion Familial hypercholesterolaemia patients had about three times higher CVD-related hospital costs and more than 10 times higher pharmaceutical costs than age- and sex-matched controls during a 10-year follow-up. During the 10 years, costs for pharmaceuticals increased and costs for hospital decreased.

• Wu, Yansi; Kunst, Natalia; Gyõrbiró, David M.; Kristiansen, Ivar Sønbø; Strand, Trond-Eirik & Nguyen, Olav Toai Duc [Show all 10 contributors for this article] (2025). Cost-effectiveness of low-dose CT lung cancer screening among individuals that have ever smoked in Norway: A model-based analysis using NELSON trial criteria and outcomes. International Journal of Cancer. ISSN 0020-7136. 158(9), p. 2452–2465. doi: 10.1002/ijc.70270. Full text in Research Archive
• Lousdal, Mette Lise; Lash, Timothy L.; Flanders, William Dana; Brookhart, M. Alan; Kristiansen, Ivar Sønbø & Vedsted, Peter [Show all 7 contributors for this article] (2025). A Quasi-experimental Study of General Practices' Referral to Mammography in the Posttrial Treatment Era. Epidemiology. ISSN 1044-3983. 36(3), p. 401–407. doi: 10.1097/EDE.0000000000001841. Full text in Research Archive
• Bugge, Christoffer; Engebretsen, Ingrid; Kristiansen, Ivar Sønbø; Sæther, Erik Magnus; Lindberg-Schager, Ingrid & Arneberg, Fredrik [Show all 7 contributors for this article] (2025). Medical costs of treating myasthenia gravis in patients who need intravenous immunoglobulin (IVIg) – a register-based study. Journal of Neurology. ISSN 0340-5354. 272. doi: 10.1007/s00415-024-12768-5. Full text in Research Archive Show summary

  Background: Several innovative treatments are expected for myasthenia gravis (MG) in the coming years. Healthcare payers usually require cost-effectiveness analyses before reimbursement. We aimed to investigate resource utilization and direct medical costs for patients with MG treated with intravenous immunoglobulin (IVIg) to inform such analyses. Methods: We identified patients with MG in the Norwegian Patient Registry based on at least two hospital encounters with an MG diagnosis (ICD-10 G70.0) from 1 Jan 2010 to 31 Dec 2021. IVIg treatment was identified by medical procedure and Anatomical Therapeutic Chemical (ATC) codes (RPGM05 and J06BA02). Using Diagnosis-Related Group (DRG) cost weights, we estimated direct medical costs for each year following the first MG diagnosis. Results: Over the study period, 1083 patients were diagnosed with MG in Norway, of whom 155 (14.3%) were treated with IVIg. No significant differences in age or sex were observed between IVIg and non-IVIg patients. Compared with non-IVIg patients, IVIg-patients had 2.3 times higher direct medical costs during the first year after MG diagnosis (EUR 35,714 vs. EUR 15,457) and 3.1 times higher costs during the second year (EUR 19,119 vs. EUR 6256). In the fifth year after diagnosis, IVIg-patients still had higher costs and resource utilization than non-IVIg patients (EUR 9953 vs. EUR 5634). Conclusion: IVIg treatment represents an important marker for high direct medical costs among patients with MG. The costs continue to be high during the first five years after MG diagnosis.

• Engebretsen, Ingrid; Ødegaard, Kristina Malene; Halvorsen, Sigrun; Bugge, Christoffer; Kristiansen, Ivar Sønbø & Støvring, Henrik [Show all 7 contributors for this article] (2024). Treatment with PCSK9 monoclonal antibodies is associated with discontinuation of oral lipid lowering therapy. European Heart Journal - Quality of Care and Clinical Outcomes. ISSN 2058-5225. doi: 10.1093/ehjqcco/qcae099. Full text in Research Archive Show summary

  Aims Proprotein convertase subtilisin/kexin type 9 monoclonal antibodies (PCSK9 mAbs) are recommended for high-risk patients if the low-density lipoprotein cholesterol targets are not achieved with statins and ezetimibe. We studied persistence and adherence to (i) PCSK9 mAbs and (ii) statins and ezetimibe in a nationwide cohort of incident PCSK9 mAb users. Methods and results Information on all PCSK9 mAb users ≤80 years from 2015 through 2023 were extracted from the Norwegian Drug Registry. Discontinuation was defined as a gap in treatment ≥180 days and ≥90 days. Adherence was measured as the proportion of days covered during the initial year of PCSK9 mAb therapy. We analysed adherence of statins and ezetimibe before and after PCSK9 mAb initiation. Of 4784 patients initiating PCSK9 mAbs, the median age was 63 years, 41% were female, 61% had atherosclerotic disease, and 34% had familial hypercholesterolaemia. Within 3 years after initiation, 17% experienced a PCSK9 mAb treatment gap exceeding 180 days. In the 12-month period preceding PCSK9 mAb initiation, 74% dispensed statins whereas 67% dispensed ezetimibe. These numbers were reduced to 35% for statins and 42% for ezetimibe during the 12-month period after PCSK9 mAb initiation. Atherosclerotic disease, using ≥3 statins previously, and older age were significantly associated with discontinuation of statins and ezetimibe. Conclusion In this high-risk cohort of incident PCSK9 mAb users, more than 1 out of 2 stopped taking statin treatment whereas 40% discontinued ezetimibe. There is a major potential for improving adherence to oral LLD treatment following initiation of PCSK9 mAb.

• Engebretsen, Ingrid; Gilhus, Nils Erik; Kristiansen, Ivar Sønbø; Sæther, Erik Magnus; Lindberg-Schager, Ingrid & Arneberg, Fredrik [Show all 7 contributors for this article] (2024). The epidemiology and societal costs of myasthenia gravis in Norway: A non-interventional study using national registry data. European Journal of Neurology. ISSN 1351-5101. 31(5). doi: 10.1111/ene.16233. Full text in Research Archive Show summary

  Background and purpose With the emergence of new treatment options for myasthenia gravis (MG), there is a need for information regarding epidemiology, healthcare utilization, and societal costs to support economic evaluation and identify eligible patients. We aimed to enhance the understanding of these factors using nationwide systematic registry data in Norway. Methods We received comprehensive national registry data from five Norwegian health- and work-related registries. The annual incidence and prevalence were estimated for the period 2013–2021 using nationwide hospital and prescription data. The direct, indirect (productivity losses) and intangible costs (value of lost life-years [LLY] and health-related quality of life [HRQoL]) related to MG were estimated over a period of 1 year. Results In 2021, the incidence of MG ranged from 15 to 16 cases per year per million population depending on the registry used, while the prevalence varied between 208.9 and 210.3 per million population. The total annual societal costs of MG amounted to EUR 24,743 per patient, of which EUR 3592 (14.5%) were direct costs, EUR 8666 (35.0%) were productivity loss, and EUR 12,485 (50.5%) were lost value from LLY and reduced HRQoL. Conclusion The incidence and prevalence of MG are higher than previously estimated, and the total societal costs of MG are substantial. Our findings demonstrate that productivity losses, and the value of LLY and HRQoL constitute a considerable proportion of the total societal costs.

• Røssell, Eeva-Liisa; Bekker, Hilary Louise; Schonberg, Mara A.; Kristiansen, Ivar Sønbø; Borgquist, Signe & Støvring, Henrik (2024). Danish Women Make Decisions about Participation in Breast Cancer Screening prior to Invitation Information: An Online Survey Using Experimental Methods. Medical decision making. ISSN 0272-989X. doi: 10.1177/0272989X241248142. Full text in Research Archive
• Nielsen, Jesper Bo; Kristiansen, Ivar Sønbø & Thapa, Subash (2024). Increasing melanoma incidence with unchanged mortality: more sunshine, better treatment, increased diagnostic activity, overdiagnosis or lowered diagnostic threshold? British Journal of Dermatology. ISSN 0007-0963. 191(3), p. 365–374. doi: 10.1093/bjd/ljae175. Full text in Research Archive
• Pedersen, Kine; Kristiansen, Ivar Sønbø; Sy, Stephen; Kim, Jane J. & Burger, Emily Annika (2023). Designing Guidelines for Those Who Do Not Follow Them: The Impact of Adherence Assumptions on Optimal Screening Guidelines. Value in Health. ISSN 1098-3015. doi: 10.1016/j.jval.2023.04.005. Full text in Research Archive Show summary

  Objectives Model-based cost-effectiveness analyses can inform decisions about screening guidelines by quantifying consequences of alternative algorithms. Although actual screening adherence is imperfect, incorporating nonadherence into analyses that aim to determine optimal screening may affect the policy recommendations. We evaluated the impact of nonadherence assumptions on the optimal cervical cancer screening in Norway. Methods We used a microsimulation model of cervical carcinogenesis to project the long-term health and economic outcomes under alternative screening algorithms and adherence patterns. We compared 18 algorithms involving primary human papillomavirus testing (5-yearly) that varied follow-up management of different human papillomavirus results. We considered 12 adherence scenarios: perfect adherence, 8 high- and low-coverage “random-complier” scenarios, and 3 “systematic-complier” scenarios that reflect conditional screening behavior over a lifetime. We calculated incremental cost-effectiveness ratios and considered a strategy with the highest incremental cost-effectiveness ratio < 55 000 US dollars/quality-adjusted life-year as “optimal.” Results Under perfect adherence, the least intensive screening strategy was optimal; in contrast, assuming any nonadherence resulted in a more intensive optimal strategy. Accounting for lower adherence resulted in both lower costs and health benefits, which allowed for a more intensive strategy to be considered optimal, but more harms for women who screen according to guidelines (ie, up to 41% more colposcopies when comparing the optimal strategy in the lowest-adherence scenario with the optimal strategy under perfect adherence). Conclusions Assuming nonadherence in analyses designed to inform national guidelines may lead to a relatively more intensive recommendation. Designing guidelines for those who do not adhere to them may lead to over-screening of those who do.

• Husum, Yngvil Solheim; Bråten, Ragnhild Haugli; Sæther, Erik Magnus; Moe, Morten Carsten; Kristiansen, Ivar Sønbø & Jørstad, Øystein Kalsnes (2023). Intravitreal anti-vascular endothelial growth factor therapy for retinal diseases in Norway from 2011 to 2021: A combined registry and survey study. Acta Ophthalmologica. ISSN 1755-375X. p. 1–11. doi: 10.1111/aos.16598. Full text in Research Archive
• Røssell, Eeva-Liisa; Bo, Anne; Grønborg, Therese Koops; Kristiansen, Ivar Sønbø; Borgquist, Signe & Scherer, Laura D. [Show all 7 contributors for this article] (2023). Danish Women Want to Participate in a Hypothetical Breast Cancer Screening with Harms and No Reduction in Mortality: A Cross-Sectional Survey. Medical decision making. ISSN 0272-989X. doi: 10.1177/0272989X231152830. Full text in Research Archive
• Engebretsen, Ingrid; Munkhaugen, John; Bugge, Christoffer; Halvorsen, Sigrun; Ødegaard, Kristina Malene & Støvring, Henrik [Show all 7 contributors for this article] (2022). Gaps and discontinuation of statin treatment in Norway: potential for optimizing management of lipid lowering drugs. European Heart Journal Open (EHJ Open). 2(6). doi: 10.1093/ehjopen/oeac070. Full text in Research Archive Show summary

  Abstract Aims In clinical practice many patients do not reach the recommended treatment targets for LDL-cholesterol levels. We aimed to examine treatment patterns and adherence for patients on lipid lowering drugs in Norway to inform future strategies to improve therapies. Methods and results We obtained information on all dispensed statins, ezetimibe and PCSK9 inhibitors 2010-2019 from the Norwegian Prescription Database. Treatment gaps were assessed assuming patients take one tablet per day and was defined to occur if a patient did not refill a prescription when the previous one should have been depleted. Treatment was defined as discontinued when the preceding prescription would have been used and no new subsequent prescription was filled. The mean proportion of days covered (PDC) was calculated by aggregating the total number of tablets dispensed during each calendar year and dividing by 365. Patients >80 years were excluded. A considerable proportion of statin users in Norway had long treatment gaps or discontinuation in treatment. 19.6% of the patients had treatment gaps of 180 days or more, and 10.8% had gaps or greater than 365 days. Similar results were found for patients on antidiabetics and hypertensives. PDC ranged from 84.9% for simvastatin to 72.2% for ezetimibe (2019). The most common lipid lowering drugs in 2019 were atorvastatin, simvastatin and ezetimibe. Conclusion There is a great potential for improving drug adherence and optimizing lipid lowering therapy by switching to more effective statins in greater doses, and more Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation often add ezetimibe and PCSK9 inhibitors to treatment.

• Nielsen, Jesper B.; Kristiansen, Ivar Sønbø & Thapa, Subash (2022). Prolongation of disease-free life: When is the benefit sufficient to warrant the effort of taking a preventive medicine? Preventive Medicine. ISSN 0091-7435. 154. doi: 10.1016/j.ypmed.2021.106867. Full text in Research Archive
• Cyr, Pascale Renée; Pedersen, Kine; Iyer, Anita Lakshmi; Bundorf, Kate; Goldhaber-Fiebert, Jeremy & Gyrd-Hansen, Dorte [Show all 8 contributors for this article] (2021). Providing more balanced information on the harms and benefits of cervical cancer screening: A randomized survey among US and Norwegian women. Preventive Medicine Reports. doi: 10.1016/j.pmedr.2021.101452. Full text in Research Archive Show summary

  We aimed to identify how additional information about benefits and harms of cervical cancer (CC) screening impacted intention to participate in screening, what type of information on harms women preferred receiving, from whom, and whether it differed between two national healthcare settings. We conducted a survey that randomized screen-eligible women in the United States (n = 1084) and Norway (n = 1060) into four groups according to the timing of introducing additional information. We found that additional information did not significantly impact stated intentions-to-participate in screening or follow-up testing in either country; however, the proportion of Norwegian women stating uncertainty about seeking precancer treatment increased from 7.9% to 14.3% (p = 0.012). Women reported strong system-specific preferences for sources of information: Norwegians (59%) preferred it come from a national public health agency while Americans (59%) preferred it come from a specialist care provider. Regression models revealed having a prior Pap-test was the most important predictor of intentions-to-participate in both countries, while having lower income reduced the probabilities of intentions-to-follow-up and seek precancer treatment among U.S. women. These results suggest that additional information on harms is unlikely to reduce participation in CC screening but could increase decision uncertainty to seek treatment. Providing unbiased information would improve on the ethical principle of respect for autonomy and self-determination. However, the clinical impact of additional information on women's understanding of the trade-offs involved with CC screening should be investigated. Future studies should also consider country-specific socioeconomic barriers to screening if communication re-design initiatives aim to improve CC screening participation.

• Bugge, Christoffer; Brustugun, Odd Terje; Sæther, Erik Magnus & Kristiansen, Ivar Sønbø (2021). Phase- and gender-specific, lifetime, and future costs of cancer: A retrospective population-based registry study. Medicine. ISSN 0025-7974. 100(26), p. 1–8. doi: 10.1097/MD.0000000000026523. Full text in Research Archive
• Bugge, Christoffer; Kaasa, Stein; Sæther, Erik Magnus; Melberg, Hans Olav & Kristiansen, Ivar Sønbø (2021). What are determinants of utilisation of pharmaceutical anticancer treatment during the last year of life in Norway? A retrospective registry study. BMJ Open. 11(9), p. 1–7. doi: 10.1136/bmjopen-2021-050564. Full text in Research Archive
• Oteiza, Francisco; Løyland, Hanna Isabel; Bugge, Christoffer; Kristiansen, Ivar Sønbø & Støvring, Henrik (2021). Persistence of statin treatment – the impact of analytic method when estimating drug survival. Norsk Epidemiologi. ISSN 0803-2491. 29(1-2), p. 107–115. doi: 10.5324/nje.v29i1-2.4052. Full text in Research Archive
• Bugge, Christoffer; Sæther, Erik Magnus; Brustugun, Odd & Kristiansen, Ivar Sønbø (2021). Societal cost of cancer in Norway –Results of taking a broader cost perspective. Health Policy. ISSN 0168-8510. doi: 10.1016/j.healthpol.2021.05.008. Full text in Research Archive
• Bugge, Christoffer; Sæther, Erik Magnus & Kristiansen, Ivar Sønbø (2021). Men receive more end-of-life cancer hospital treatment than women: fact or fiction? Acta Oncologica. ISSN 0284-186X. 60(8), p. 984–991. doi: 10.1080/0284186X.2021.1917000. Full text in Research Archive
• Lousdal, Mette Lise; Lash, Timothy L.; Flanders, W Dana; Brookhart, M Alan; Kristiansen, Ivar Sønbø & Kalager, Mette [Show all 7 contributors for this article] (2020). Negative controls to detect uncontrolled confounding in observational studies of mammographic screening comparing participants and non-participants. International Journal of Epidemiology. ISSN 0300-5771. 49(3), p. 1032–1042. doi: 10.1093/ije/dyaa029. Full text in Research Archive
• Hovland, Ragnar; Bremer, Sara; Frigaard, Christine; Henjum, Solveig; Faksvåg, Per Kristian & Sæther, Erik Magnus [Show all 7 contributors for this article] (2019). Effect of a pharmacist-led intervention on adherence among patients with a first-time prescription for a cardiovascular medicine: a randomized controlled trial in Norwegian pharmacies. International Journal of Pharmacy Practice (IJPP). ISSN 0961-7671. doi: 10.1111/ijpp.12598. Full text in Research Archive
• Wisløff, Torbjørn; Mundal, Liv; Retterstøl, Kjetil; Igland, Jannicke & Kristiansen, Ivar Sønbø (2019). Economic evaluation of lipid lowering with PCSK9 inhibitors in patients with familial hypercholesterolemia: Methodological aspects. Atherosclerosis. ISSN 0021-9150. 287, p. 140–146. doi: 10.1016/j.atherosclerosis.2019.06.900. Full text in Research Archive Show summary

  Background and aims: Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have proved to reduce low density lipoprotein cholesterol levels in numerous clinical trials. In two large clinical trials, PCSK9 inhibitor treatment reduced the risk of cardiovascular disease. Our aim was to explore the impact of varying assumptions about clinical effectiveness on health and economic outcomes for patients with familial hypercholesterolemia. Methods: We used a previously published and validated Norwegian model for cardiovascular disease. The model was updated with recent data from the world's second largest registry of patients with genetically confirmed familial hypercholesterolemia. We performed analyses for 24 different subgroups of patients based on age, gender, statin tolerance and previous history of cardiovascular disease. Results: In 1 out of 24 subgroups, PCSK9 inhibitors were cost-effective when effectiveness was modelled using direct relative efficacy as reported in the FOURIER trial. When using assumptions, as suggested in a recent consensus statement from the European Atherosclerosis Society, 14 subgroups were cost-effective. Conclusions: Cost-effectiveness of PCSK9 inhibitors depends highly on assumptions regarding effectiveness. Basing assumptions only on randomised controlled trials, and not taking into account varying effects based on baseline cholesterol level, results in much fewer groups being cost-effective.

• Kristiansen, Ivar Sønbø; Bråten, Ragnhild Haugli; Jørstad, Øystein Kalsnes; Moe, Morten Carsten & Sæther, Erik Magnus (2019). Intravitreal therapy for retinal diseases in Norway 2011-2015. Acta Ophthalmologica. ISSN 1755-375X. p. 1–7. doi: 10.1111/aos.14262. Full text in Research Archive Show summary

  Purpose During the past decade, intravitreally administered biologic drugs have advanced the treatment of retinal diseases, such as wet age‐related macular degeneration (AMD), diabetic macular oedema and retinal venous occlusions. The drugs as well as the necessary disease management imply considerable economic burden on healthcare systems. This Norwegian study documents the rates of use of intravitreal therapies and intercounty variation over a 5‐year period. Methods We collected data from the Norwegian Patient Register for all episodes of care encompassing intravitreal therapy during the period 2011–2015. For each episode, we received information on patient age, sex, county of residence, diagnosis and name of drug injected. Results During the study period, 21 277 patients had in total 236 857 episodes of care. The number of intravitreal injections doubled from 2011 to 2015, reaching 63 601 injections in 2015, of which 77% were for diagnosed wet AMD. In 2015, the age‐adjusted number of episodes varied from 19 to 55 per 1000 population aged 50+ across Norway's 19 counties. The age‐adjusted number of patients treated per 1000 population aged 50+ varied from 5.22 to 8.35. Conclusion The use of intravitreal injections increased rapidly with wet AMD as the most frequent diagnosis and with varying utilization across Norway's 19 counties. The causes of the varying use of intravitreal therapies could not be established but may reflect variation in disease prevalence, treatment capacity, travel distance to the nearest ophthalmic service and lack of national treatment guidelines. The geographic variation in utilization may challenge policy goals of equitable care and warrants further studies.

• Edwards, Christina Hansen; Tomba, Gianpaolo Scalia; Kristiansen, Ivar Sønbø; White, Richard Aubrey & Blasio, Birgitte Freiesleben De (2019). Evaluating costs and health consequences of sick leave strategies against pandemic and seasonal influenza in Norway using a dynamic model. BMJ Open. 9. doi: 10.1136/bmjopen-2018-027832. Full text in Research Archive Show summary

  Objectives: To quantify population-level health and economic consequences of sick leave among workers with influenza symptoms. Interventions: Compared with current sick leave practice (baseline), we evaluated the health and cost consequences of: (1) increasing the proportion of workers on sick leave from 65% (baseline) to 80% or 90%; (2) shortening the maximum duration from symptom onset to sick leave from 4 days (baseline) to 2 days, 1.5 days, 1 day and 0.5 days; and (3) combinations of 1 and 2. Methods: A dynamic compartmental influenza model was developed using Norwegian population data and survey data on employee sick leave practices. The sick leave interventions were simulated under 12 different seasonal epidemic and 36 different pandemic influenza scenarios. These scenarios varied in terms of transmissibility, the proportion of symptomatic cases and illness severity (risk of primary care consultations, hospitalisations and deaths). Using probabilistic sensitivity analyses, a net health benefit approach was adopted to assess the cost-effectiveness of the interventions from a societal perspective. Results: Compared with current sick leave practice, sick leave interventions were cost-effective for 31 (65%) of the pandemic scenarios, and 11 (92%) of the seasonal scenarios. Economic benefits from sick leave interventions were greatest for scenarios with low transmissibility, high symptomatic proportions and high illness severity. Overall, the health and economic benefits were greatest for the intervention involving 90% of sick workers taking sick leave within one-half day of symptoms. Depending on the influenza scenario, this intervention resulted in a 44.4%–99.7% reduction in the attack rate. Interventions involving sick leave onset beginning 2 days or later, after the onset of symptoms, resulted in economic losses. Conclusions: Prompt sick leave onset and a high proportion of sick leave among workers with influenza symptoms may be cost-effective, particularly during influenza epidemics and pandemics with low transmissibility or high morbidity.

• Hylin, Hannah Douglass; Thrane, Helene; Pedersen, Kine; Kristiansen, Ivar Sønbø & Burger, Emily (2019). The healthcare costs of treating human papillomavirus-related cancers in Norway. BMC Cancer. 19(1). doi: 10.1186/s12885-019-5596-2. Full text in Research Archive Show summary

  Background Public health efforts to prevent human papillomavirus (HPV)-related cancers include HPV vaccination and cervical cancer screening. We quantified the annual healthcare cost of six HPV-related cancers in order to provide inputs in cost-effectiveness analyses and quantify the potential economic savings from prevention of HPV-related cancers in Norway. Methods Using individual patient-level data from three unlinked population-based registries, we estimated the mean healthcare costs 1) annually across all phases of disease, 2) during the first 3 years of care following diagnosis, and 3) for the last 12 months of life for patients diagnosed with an HPV-related cancer. We included episodes of care related to primary care physicians, specialist care (private specialists and hospital-based care and prescriptions), and prescription drugs redeemed at pharmacies outside hospitals between 2012 and 2014. We valued costs (2014 €1.00 = NOK 8.357) based on diagnosis-related groups (DRG), patient copayments, reimbursement fees and pharmacy retail prices. Results In 2014, the total healthcare cost of HPV-related cancers amounted to €39.8 million, of which specialist care accounted for more than 99% of the total cost. The annual maximum economic burden potentially averted due to HPV vaccination will be lower for vulvar, penile and vaginal cancer (i.e., €984,620, €762,964 and €374,857, respectively) than for cervical, anal and oropharyngeal cancers (i.e., €17.2 million, €6.7 million and €4.6 million, respectively). Over the first three years of treatment following cancer diagnosis, patients diagnosed with oropharyngeal cancer incurred the highest total cost per patient (i.e. €49,774), while penile cancer had the lowest total cost per patient (i.e. €18,350). In general, costs were highest the first year following diagnosis and then declined; however, costs increased rapidly again towards end of life for patients who did not survive. Conclusion HPV-related cancers constitute a considerable economic burden to the Norwegian healthcare system. As the proportion of HPV-vaccinated individuals increase and secondary prevention approaches advance, this study highlights the potential economic burden avoided by preventing these cancers.

• Sengupta, Kaushik; Thygesen, Lau Caspar; Kristiansen, Ivar Sønbø; Bolin, Kristian; Pukkala, Eero & Emneus, Martha [Show all 8 contributors for this article] (2019). Utilization of etoricoxib in dental patients in the Nordic countries: a population-based register study. Acta Odontologica Scandinavica. ISSN 0001-6357. 77(8), p. 584–591. doi: 10.1080/00016357.2019.1622037. Full text in Research Archive
• Iyer, Anita Lakshmi; Bundorf, M. Kate; Gyrd-Hansen, Dorte; Goldhaber-Flebert, Jeremy D.; Cyr, Pascale-Renée & Kristiansen, Ivar Sønbø (2019). How does information on the harms and benefits of cervical cancer screening alter the intention to be screened?: a randomized survey of Norwegian women. European Journal of Cancer Prevention. ISSN 0959-8278. 28(2), p. 87–95. doi: 10.1097/CEJ.0000000000000436. Full text in Research Archive
• Johansen, Eeva-Liisa Røssell; Lousdal, Mette Lise; Skriver, Mette Vinther; Væth, Michael; Kristiansen, Ivar Sønbø & Støvring, Henrik (2019). Predicting Difference in Mean Survival Time from Reported Hazard Ratios for Cancer Patients. Medical decision making. ISSN 0272-989X. 39(3), p. 228–238. doi: 10.1177/0272989X19832879. Full text in Research Archive
• Bugge, Christoffer; Sæther, Erik Magnus; Pahle, Andreas; Halvorsen, Sigrun & Kristiansen, Ivar Sønbø (2018). Diagnosing heart failure with NT-proBNP point-of-care testing: lower costs and better outcomes. A decision analytic study. British Journal of General Practice. ISSN 0960-1643. doi: 10.3399/bjgpopen18X101596. Full text in Research Archive
• Stavem, Knut; Augestad, Liv Ariane; Kristiansen, Ivar Sønbø & Rand, Kim (2018). General population norms for the EQ-5D-3 L in Norway: comparison of postal and web surveys. Health and Quality of Life Outcomes. 16(204), p. 1–10. doi: 10.1186/s12955-018-1029-1. Full text in Research Archive Show summary

  Background The EQ-5D-3 L instrument is a standardized questionnaire which was developed as a simple, generic measure of health for clinical and economic appraisal. To aid in the interpretation, scores are often compared with a normative group. The objectives of this study were 1) to provide population norms for the EQ-5D-3 L for Norway, and 2) to compare scores from postal and web surveys. Methods We conducted two surveys in samples that were aimed to be representative of the Norwegian general population: 1) a postal survey (n = 5000) and 2) a panel study with electronic data collection (n = 1936). For scoring the EQ-5D Index, we used the UK tariff. EQ-5D items were compared using multivariable ordinal logistic regression analysis and EQ-5D Index and EQ VAS scores using multivariable linear regression, adjusting for age, sex and education. Results In total 1131 (22.6%) responded to the postal survey and 977 (50.5%) to the web survey. The odds ratio (OR) for being in a higher score category on the Pain/Discomfort scale in the web survey was 1.25 (95%CI 1.04 to 1.50, p = 0.019) relative to the postal survey. The odds were similar in the other four dimensions. The EQ-5D Index and EQ VAS scores were similar in the postal and web surveys in the various strata according to age, sex and education, except for lower unadjusted and adjusted score for web respondents aged 41–50 years and for those with higher education (≥14 years) than postal respondents. Conclusions The distribution of scores for the EQ-5D descriptive system and its derived utility scores were rather similar in a postal survey and a panel web survey. Hence, these values were combined into a norm set for Norway.

• Lousdal, Mette Lise; Møller, Mette H.; Kristiansen, Ivar Sønbø; Kalager, Mette; Wisløff, Torbjørn & Støvring, Henrik (2018). The Screening Illustrator: separating the effects of lead-time and overdiagnosis in mammography screening. European Journal of Public Health. ISSN 1101-1262. 28(6), p. 1138–1142. doi: 10.1093/eurpub/cky085. Full text in Research Archive
• Korman, Max; Retterstøl, Kjetil; Kristiansen, Ivar Sønbø & Wisløff, Torbjørn (2018). Are PCSK9 Inhibitors Cost Effective? PharmacoEconomics (Auckland). ISSN 1170-7690. 36(9), p. 1031–1041. doi: 10.1007/s40273-018-0671-0. Full text in Research Archive Show summary

  The objective of this study was to review available health economic evaluations of PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors. These drugs reduce low-density lipid cholesterol levels and cardiovascular risk, but their cost effectiveness has been questioned. We searched Medline and Embase for economic evaluations in any language at any time. Studies were included if they analysed any PCSK9 inhibitor compared with either statin alone or in combination with ezetimibe or any other therapy considered standard prior to the introduction of PCSK9 inhibitors. We found ten full health economic evaluations of PCSK9 inhibitors, two from Europe and eight from the United States (US). Six of the eight from the US were from two different consortia that analysed PCSK9 inhibitors at different stages through the development of evidence. All studies generally reported incremental cost-effectiveness ratios above suggested thresholds for cost effectiveness, except one study from Spain. The results of this review indicate that PCSK9 inhibitors in general are not cost effective at the current prices, but lower prices may change the results.

• Møller, Mette; Lousdal, Mette Lise; Kristiansen, Ivar Sønbø & Støvring, Henrik (2018). Effect of organized mammography screening on breast cancer mortality: A population-based cohort study in Norway. International Journal of Cancer. ISSN 0020-7136. p. 1–10. doi: 10.1002/ijc.31832. Full text in Research Archive
• Inderhaug, Eivind; Schelp, Carl Henrik; Glambek, Inge & Kristiansen, Ivar Sønbø (2018). Cost-effectiveness analysis of five procedures for great saphenous vein reflux in a Norwegian healthcare setting or societal setting. American Journal of Sports Medicine. ISSN 0363-5465. 6(4), p. 826–831. doi: 10.1177/2050312118801709. Full text in Research Archive
• Pedersen, Kine; Fogelberg, Sara; Thamsborg, Lise H.; Clements, Mark; Nygård, Mari & Kristiansen, Ivar Sønbø [Show all 10 contributors for this article] (2018). An overview of cervical cancer epidemiology and prevention in Scandinavia. Acta Obstetricia et Gynecologica Scandinavica. ISSN 0001-6349. 97(7), p. 795–807. doi: 10.1111/aogs.13313. Full text in Research Archive Show summary

  New technologies such as human papillomavirus (HPV) testing and vaccination necessitate comprehensive policy analyses to optimize cervical cancer prevention. To inform future Scandinavian‐specific policy analyses, we aimed to provide an overview of cervical cancer epidemiology and existing prevention efforts in Denmark, Norway and Sweden. We compiled and summarized data on current prevention strategies, population demography and epidemiology (for example, age‐specific HPV prevalence and cervical cancer incidence over time) for each Scandinavian country by reviewing published literature and official guidelines, performing registry‐based analyses using primary data and having discussions with experts in each country. In Scandinavia, opportunistic screening occurred as early as the 1950s and by 1996, all countries had implemented nationwide organized cytology‐based screening. Prior to implementation of widespread screening and during 1960–66, cervical cancer incidence was considerably higher in Denmark than in Norway and Sweden. Decades of cytology‐based screening later (i.e. 2010–2014), cervical cancer incidence has been considerably reduced and has converged across the countries since the 1960s, although it still remains lowest in Sweden. Generally, Scandinavian countries face similar cervical cancer burdens and utilize similar prevention approaches; however, important differences remain. Future policy analyses will need to evaluate whether these differences warrant differential prevention policies or whether efforts can be streamlined across Scandinavia.

• Mundal, Liv; Igland, Jannicke; Veierød, Marit Bragelien; Holven, Kirsten Bjørklund; Ose, Leiv & Selmer, Randi [Show all 11 contributors for this article] (2018). Impact of age on excess risk of coronary heart disease in patients with familial hypercholesterolaemia. Heart. ISSN 1355-6037. 104(19), p. 1600–1607. doi: 10.1136/heartjnl-2017-312706. Full text in Research Archive Show summary

  Objective: The primary objective was to study the risk of acute myocardial infarction (AMI) and coronary heart disease (CHD) in patients with familial hypercholesterolaemia (FH) and compare with the risk in the general population. Methods: Patients with an FH mutation but without prior AMI (n=3071) and without prior CHD (n=2795) were included in the study sample during 2001–2009. We obtained data on all AMI and CHD hospitalisations in Norway. We defined incident cases as first time hospitalisation or out-of-hospital death due to AMI or CHD. We estimated standardised incidence ratios (SIRs) with 95% CIs with indirect standardisation using incidence rates for the total Norwegian population stratified by sex, calendar year and 1 year age groups as reference rates. Results: SIRs for AMI (95% CIs) were highest in the age group 25–39 years; 7.5 (3.7 to 14.9) in men and 13.6 (5.1 to 36.2) in women and decreased with age to 0.9 (0.4 to 2.1) in men and 1.8 (0.9 to 3.7) in women aged 70–79 years. Similarly, SIRs for CHD were highest among patients 25–39 years old; 11.1 (7.1–17.5) in men and 17.3 (9.6–31.2) in women and decreased 2.4 (1.4–4.2) in men and 3.2 (1.5–7.2) in women at age 70–79. For all age groups, combined SIRs for CHD were 4.2 (3.6–5.0) in men and 4.7 (3.9–5.7) in women. Conclusion: Patients with FH are at severely increased risk of AMI and CHD compared with the general population. The highest excess risk was in the youngest group aged 25–39 years, in both sexes.

• Pedersen, Kine; Burger, Emily; Nygård, Mari; Kristiansen, Ivar Sønbø & Kim, Jane J. (2018). Adapting cervical cancer screening for women vaccinated against human papillomavirus infections: The value of stratifying guidelines. European Journal of Cancer. ISSN 0959-8049. 91, p. 68–75. doi: 10.1016/j.ejca.2017.12.018. Full text in Research Archive Show summary

  Background Several countries have implemented vaccination against human papillomavirus (HPV) for adolescent girls and must decide whether and how to adapt cervical cancer (CC) screening for these low-risk women. We aimed to identify the optimal screening strategies for women vaccinated against HPV infections and quantify the amount that could be spent to identify vaccination status among women and stratify CC screening guidelines accordingly. Methods We used a mathematical model reflecting HPV-induced CC in Norway to project the long-term health benefits, resources and costs associated with 74 candidate-screening strategies that varied by screening test, start age and frequency. Strategies were considered separately for women vaccinated with the bivalent/quadrivalent (2/4vHPV) and nonavalent (9vHPV) vaccines. We used a cost-effectiveness framework (i.e. incremental cost-effectiveness ratios and net monetary benefit) and a commonly-cited Norwegian willingness-to-pay threshold of €75,000 per quality-adjusted life-year gained. Results The most cost-effective screening strategy for 9vHPV- and 2/4vHPV-vaccinated women involved HPV testing once and twice per lifetime, respectively. The value of stratifying guidelines by vaccination status was €599 (2/4vHPV) and €725 (9vHPV) per vaccinated woman. Consequently, for the first birth cohort of ∼22,000 women who were vaccinated in adolescence in Norway, between €10.5–13.2 million over their lifetime could be spent on identifying individual vaccination status and stratify screening while remaining cost-effective. Conclusion Less intensive strategies are required for CC screening to remain cost-effective in HPV-vaccinated women. Moreover, screening can remain cost-effective even if large investments are made to identify individual vaccination status and stratify screening guidelines accordingly. Pedersen, Kine, et al. "Adapting cervical cancer screening for women vaccinated against human papillomavirus infections: The value of stratifying guidelines." European Journal of Cancer 91 (2018): 68-75. © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license.

• Pahle, Andreas; Sørli, Daniel; Kristiansen, Ivar Sønbø; Deraas, Trygve Sigvart & Halvorsen, Peder Andreas (2017). Practice variation in surgical procedures and IUD-insertions among general practitioners in Norway – a longitudinal study. BMC Family Practice. 18:7. doi: 10.1186/s12875-017-0581-9. Full text in Research Archive Show summary

  Background: Studies of Primary Health Care (PHC) reveal considerable practice variations in terms of the range of services provided. In Norway, general practitioners (GPs) are traditionally expected to perform IUD-insertions and several surgical procedures as a part of comprehensive PHC. We aimed to investigate variation in the provision of surgical procedures and IUD-insertions across GPs and over time and explore determinants of such variation. Methods: Retrospective registry study of Norwegian GPs. From a comprehensive database of GPs’ reimbursement claims, we obtained procedure codes and GP characteristics such as age, gender, list size and municipality characteristics from 2006 through 2013. Multivariable logistic regression models were fitted to explore determinants of practice variation. Results: We extracted data from 4,828 GPs. In 2013, 91.0, 76.1 and 74.8% were reimbursed at least once for minor and major surgical procedures and IUD-insertion, respectively. Female GPs had lower odds for performing major surgical procedures (OR 0.38, 95% CI 0.32–0.45) and higher odds for performing IUD-insertions (OR 6.28, 95% CI 4. 47–8.82) than male GPs. Older GPs and GPs with shorter patient lists were less likely to perform surgical procedures. GPs with longer patient lists had higher odds for performing IUD-insertions. The proportion of GPs performing surgical procedures increased over time, while the proportion decreased for IUD-insertions. The number of IUD-insertions in specialist care increased from 12,575 in 2011 to 15 216 (+21.0%) in 2014. Conclusion: We observed a large variation in the provision of surgical procedures and IUD-insertions amongst GPs in Norway. The GPs’ age, gender, list size and size of municipality were associated with performing the procedures. Our findings suggest a shift of IUD-insertions from primary to specialist care.

• Pedersen, Kine; Sørbye, Sveinung Wergeland; Kristiansen, Ivar Sønbø & Burger, Emily (2017). Using novel biomarkers to triage young adult women with minor cervical lesions: a cost-effectiveness analysis. BJOG: An International Journal of Obstetrics and Gynaecology. ISSN 1470-0328. 124(3), p. 474–484. doi: 10.1111/1471-0528.14135. Full text in Research Archive Show summary

  Objective To evaluate the short-term consequences and cost-effectiveness associated with the use of novel biomarkers to triage young adult women with minor cervical cytological lesions. Design Model-based economic evaluation using primary epidemiological data from Norway, supplemented with data from European and American clinical trials. Setting Organised cervical cancer screening in Norway. Population Women aged 25–33 years with minor cervical cytological lesions detected at their primary screening test. Methods We expanded an existing simulation model to compare 12 triage strategies involving alternative biomarkers (i.e. reflex human papillomavirus (HPV) DNA/mRNA testing, genotyping, and dual staining) with the current Norwegian triage guidelines. Main outcome measures The number of high-grade precancers detected and resource use (e.g. monetary costs and colposcopy referrals) for a single screening round (3 years) for each triage strategy. Cost-efficiency, defined as the additional cost per additional precancer detected of each strategy compared with the next most costly strategy. Results Five strategies were identified as cost-efficient, and are projected to increase the precancer detection rate between 18 and 57%, compared with current guidelines; however, the strategies did not uniformly require additional resources. Strategies involving HPV mRNA testing required fewer resources, whereas HPV DNA-based strategies detected >50% more precancers, but were more costly and required twice as many colposcopy referrals compared with the current guidelines. Conclusion Strategies involving biomarkers to triage younger women with minor cervical cytological lesions have the potential to detect additional precancers, yet the optimal strategy depends on the resources available as well as decision-makers' and women's acceptance of additional screening procedures.

• Burger, Emily; Pedersen, Kine; Sy, Stephen; Kristiansen, Ivar Sønbø & Kim, Jane J (2017). Choosing wisely: a model-based analysis evaluating the trade-offs in cancer benefit and diagnostic referrals among alternative HPV testing strategies in Norway. British Journal of Cancer. ISSN 0007-0920. 117(6), p. 783–790. doi: 10.1038/bjc.2017.248. Full text in Research Archive Show summary

  Background: Forthcoming cervical cancer screening strategies involving human papillomavirus (HPV) testing for women not vaccinated against HPV infections may increase colposcopy referral rates. We quantified health and resource trade-offs associated with alternative HPV-based algorithms to inform decision-makers when choosing between candidate algorithms. Methods: We used a mathematical simulation model of HPV-induced cervical carcinogenesis in Norway. We compared the current cytology-based strategy to alternative strategies that varied by the switching age to primary HPV testing (ages 25–34 years), the routine screening frequency (every 3–10 years), and management of HPV-positive, cytology-negative women. Model outcomes included reductions in lifetime cervical cancer risk, relative colposcopy rates, and colposcopy rates per cervical cancer prevented. Results: The age of switching to primary HPV testing and the screening frequency had the largest impacts on cancer risk reductions, which ranged from 90.9% to 96.3% compared to no screening. In contrast, increasing the follow-up intensity of HPV-positive, cytology-negative women provided only minor improvements in cancer benefits, but generally required considerably higher rates of colposcopy referrals compared to current levels, resulting in less efficient cervical cancer prevention. Conclusions: We found that in order to maximise cancer benefits HPV-based screening among unvaccinated women should not be delayed: rather, policy makers should utilise the triage mechanism to control colposcopy referrals.

• Andreassen, A Elizabeth S; Jacobsen, Caroline M; Blasio, Birgitte Freiesleben De; White, Richard; Kristiansen, Ivar Sønbø & Elstrøm, Petter (2017). The impact of methicillin-resistant S. aureus on length of stay, readmissions and costs: a register based case-control study of patients hospitalized in Norway. Antimicrobial Resistance & Infection Control. 6. doi: 10.1186/s13756-017-0232-x. Full text in Research Archive Show summary

  Background: Patients with methicillin-resistant S. aureus (MRSA) are thought to incur additional costs for hospitals due to longer stay and contact isolation. The aim of this study was to assess the costs associated with MRSA in Norwegian hospitals. Methods: Analyses were based on data fromSouth-Eastern Norway for the year 2012 as registered in the Norwegian Surveillance System for Communicable Diseases and the Norwegian Patient Registry. We used a matched case-control method to compare MRSA diagnosed inpatients with non-MRSA inpatients in terms of length of stay, readmissions within 30 days from discharge, as well as the Diagnosis-Related Group (DRG) based costs. Results: Norwegian patients with MRSA stayed on average 8 days longer in hospital than controls, corresponding to a ratio of mean duration of 2.08 (CI 95%, 1.75–2.47) times longer.A total of 14% of MRSA positive inpatients were readmitted compared to 10% among controls. However, the risk of readmission was not significantly higher for patients with MRSA. DRG based hospital costs were 0.37 (95% CI, 0.19–0.54) times higher among cases than controls, with a mean cost of EUR13,233(SD 26,899) and EUR7198(SD 18,159) respectively. Conclusion: The results of this study indicate that Norwegian patients with MRSA have longer hospital stays, and higher costs than those without MRSA.

• Lousdal, Mette Lise; Kristiansen, Ivar Sønbø; Møller, Bjørn & Støvring, Henrik (2017). Predicting Mean Survival Time from Reported Median Survival Time for Cancer Patients. Medical decision making. ISSN 0272-989X. 37(4), p. 391–402. doi: 10.1177/0272989X16655341. Full text in Research Archive
• Shin, Minkyung; Salamanca, Beatriz Valcarcel; Kristiansen, Ivar Sønbø & Flem, Elmira (2016). Healthcare Costs of Rotavirus and Other Types of Gastroenteritis in Children in Norway. The Pediatric Infectious Disease Journal. ISSN 0891-3668. 35(4), p. e97–e101. doi: 10.1097/INF.0000000000001026. Full text in Research Archive Show summary

  BACKGROUND: Norway has initiated a publicly funded rotavirus immunization program for all age-eligible children in 2014. We aimed to estimate the healthcare costs of rotavirus gastroenteritis in children younger than 5 years of age. METHODS: We identified all gastroenteritis cases in children younger than 5 years old treated during 2009-2013 through the national claims database for primary care and the national hospital registry. We estimated direct medical costs of rotavirus-associated primary care consultations and hospital encounters (inpatient admission, outpatient visit, and ambulatory care). We performed a range of one-way sensitivity analyses to explore uncertainty in the cost estimates. RESULTS: Prior to vaccine introduction, the mean healthcare cost of rotavirus gastroenteritis in children younger than 5 years of age was &OV0556;4,440,337 million per year. Among rotavirus-associated costs, 92% were hospital costs and the remaining 8% were primary care costs. The mean annual cost of rotavirus-associated hospital encounters was &OV0556;4,083,691, of which 95% were costs of inpatient hospital admissions. The average healthcare cost of medically attended gastroenteritis in children younger than 5 years of age was approximately &OV0556;8 million per year, of which rotavirus-related costs represented 56%. CONCLUSIONS: Healthcare costs of rotavirus gastroenteritis in Norway are substantial. The cost-effectiveness of ongoing rotavirus immunization program should be reassessed.

• Lousdal, Mette L; Kristiansen, Ivar Sønbø; Møller, Bjørn & Støvring, Henrik (2016). Effect of organised mammography screening on stage-specific incidence in Norway: Population study. British Journal of Cancer. ISSN 0007-0920. 114(5), p. 590–596. doi: 10.1038/bjc.2016.8. Full text in Research Archive
• Augestad, Liv Ariane; Stavem, Knut; Kristiansen, Ivar Sønbø; Samuelsen, Carl Haakon & Rand-Hendriksen, Kim (2016). Influenced from the start: anchoring bias in time trade-off valuations. Quality of Life Research. ISSN 0962-9343. 25(9), p. 1–13. doi: 10.1007/s11136-016-1266-x. Full text in Research Archive
• Møller, MH; Kristiansen, Ivar Sønbø; Beisland, Christian; Rørvik, Jarle & Støvring, H (2016). Trends in stage-specific incidence of prostate cancer in Norway, 1980–2010: a population-based study. BJU International. ISSN 1464-4096. 118(4), p. 547–555. doi: 10.1111/bju.13364. Full text in Research Archive Show summary

  OBJECTIVES: To estimate changes in the stage distribution of prostate cancer during the time period where opportunistic PSA-testing was introduced. SUBJECTS AND METHODS: Cancer stage, age and year of diagnosis were obtained for all men over the age of 50 diagnosed with prostate cancer in Norway during the period 1980-2010. Three calendar-time periods (1980-1989, 1990-2000, and 2001-2010) and three age groups (50-65, 66-74, and 75+) were defined. Birth cohorts were categorized into four intervals: <1915, 1916-1925, 1926-1940 and >1941. We used Poisson regressions to conduct both a time period and cohort-based analysis of trends in the incidence of localised, regional and distant cancer for each combination of age groups and calendar-time periods or birth cohorts, respectively. Additionally, we explored the effect of cohorts on the stage-specific incidence graphically with a Poisson regression using 5-year age groups, and by estimating cumulative incidence rates for each birth cohort. RESULTS: The annual incidence of localised cancers among men aged 50-65 and 66-74 rose from 41.4 and 255.2 per 100,000, respectively, before the introduction of PSA-testing to 137.9 and 418.7 in 2001-2010 afterwards, corresponding to 3.3 (CI: 3.1; 3.5) and 1.6 (CI: 1.6; 1.7) fold increases. The incidence of regional cancers increased by a factor seven among men aged <75. The incidence of distant cancers in men aged 75+ decreased by 29% (CI: 25%; 33%). These findings were confirmed in the cohort-based approach. CONCLUSION: Opportunistic PSA-testing substantially increased the incidence of localised and regional prostate cancers among men aged 50-74 years, which was not fully compensated by the 30% decrease in incidence of distant prostate cancers in older men. This article is protected by copyright. All rights reserved.

• Pedersen, Kine; Burger, Emily; Sy, Stephen; Kristiansen, Ivar Sønbø & Kim, Jane J. (2016). Cost-effective management of women with minor cervical lesions: Revisiting the application of HPV DNA testing. Gynecologic Oncology. ISSN 0090-8258. 143(2), p. 326–333. doi: 10.1016/j.ygyno.2016.08.231. Full text in Research Archive Show summary

  Background Lack of consensus in management guidelines for women with minor cervical lesions, coupled with novel screening approaches, such as human papillomavirus (HPV) genotyping, necessitate revisiting prevention policies. We evaluated the cost-effectiveness and resource trade-offs of alternative triage strategies to inform cervical cancer prevention in Norway. Methods We used a decision-analytic model to compare the lifetime health and economic consequences associated with ten novel candidate approaches to triage women with minor cervical lesions. Candidate strategies varied by: 1) the triage test(s): HPV testing in combination with cytology, HPV testing alone with or without genotyping for HPV-16 and -18, and immediate colposcopy, and 2) the length of time between index and triage testing (i.e., 6, 12 or 18 months). Model outcomes included quality-adjusted life-years (QALYs), lifetime societal costs, and resource use (e.g., colposcopy referrals). Results The current Norwegian guidelines were less effective and more costly than candidate strategies. Given a commonly-cited willingness-to-pay threshold in Norway of $100,000 per QALY gained, the preferred strategy involved HPV genotyping with immediate colposcopy referral for HPV-16 or -18 positive and repeat HPV testing at 12 months for non-HPV-16 or -18 positive ($78,010 per QALY gained). Differences in health benefits among candidate strategies were small, while resource use varied substantially. More effective strategies required a moderate increase in colposcopy referrals (e.g., a 9% increase for the preferred strategy) compared with current levels. Conclusion New applications of HPV testing may improve management of women with minor cervical lesions, yet are accompanied by a trade-off of increased follow-up procedures.

• Hagen, Gunhild; Wisløff, Torbjørn & Kristiansen, Ivar Sønbø (2016). The predicted lifetime costs and health consequences of calcium and vitamin D supplementation for fracture prevention—the impact of cardiovascular effects. Osteoporosis International. ISSN 0937-941X. 27(6), p. 2089–2098. doi: 10.1007/s00198-016-3495-9. Full text in Research Archive
• Halvorsen, Peder Andreas; Aasland, Olaf Gjerløw & Kristiansen, Ivar Sønbø (2015). Decisions on statin therapy by patients’ opinions about survival gains: cross sectional survey of general practitioners. BMC Family Practice. 16. doi: 10.1186/s12875-015-0288-8. Full text in Research Archive Show summary

  Background: Guidelines for primary prevention of cardiovascular disease provide little guidance on how patients’ preferences should be taken into account. We wanted to explore whether general practitioners (GPs) are sensitive to patient preferences regarding survival gains from statin therapy. Methods: In a cross sectional, online survey 3,270 Norwegian GPs were presented with a 55 year old patient with an unfavourable cardiovascular risk profile. He expressed preferences for statin therapy by indicating a minimum survival gain that would be considered a substantial benefit. This survival gain varied across six versions of the vignette: 8, 4 and 2 years, and 12, 6 and 3 months, respectively. Participants were randomly allocated to one version only. We asked whether the GPs would recommend the patient to take a statin. Subsequently we asked the GPs to estimate the average survival gain of life long simvastatin therapy for patients with a similar risk profile. Results: We received 1,296 responses (40 %). Across levels of survival gains (8 years to 3 months) the proportion of GPs recommending statin therapy did not vary significantly (OR per level 1.07, 95 % CI 0.99 to 1.16). The GP’s own estimate of survival gain was a statistically significant predictor of recommending therapy (OR per year adjusted for the GPs’ age, sex, speciality attainment and number of patients listed 3.07, CI 2.55 to 3.69). Conclusion: GPs were insensitive to patient preferences regarding survival gain when recommending statin therapy. The GPs' recommendations were strongly associated with their own estimates of survival gain

• Pedersen, Kine; Lönnberg, Stefan; Skare, Gry Baadstrand; Sørbye, Sveinung Wergeland; Burger, Emily & Kristiansen, Ivar Sønbø (2015). Kostnader ved Masseundersøkelsen mot livmorhalskreft. Sykepleien Forskning. ISSN 1890-2936. p. 62–71. doi: 10.4220/Sykepleienf.2015.53414. Full text in Research Archive Show summary

  Bakgrunn: Forebygging står sentralt i norsk helsepolitikk, og observasjonsstudier tyder på at organisert screening har redusert forekomsten av livmorhalskreft i Norge. Samfunnets ressurser er imidlertid knappe. Hensikt: Vår hensikt var å estimere de årlige kostnadene av Masseundersøkelsen mot livmorhalskreft. Metode: Vi beregnet statens direkte utgifter og de årlige samfunnsøkonomiske kostnader av dagens screeningprogram for livmorhalskreft på grunnlag av opplysninger fra Kreftregisteret om antall utførte undersøkelser under Masseundersøkelsen for livmorhalskreft og enhetskostnadene for disse. De samfunnsøkonomiske enhetskostnadene er basert på ulike beregninger av faktiske kostnader, mens statens utgifter er basert på de ulike takstsystemer. Resultater: I 2011 ble det utført i alt 360 704 primærscreeningprøver, som med våre beregninger ville medføre 21 783 nye etterundersøkelser. Det ble innsendt biopsier for omtrent 9000 kvinner, og 3057 kvinner fikk utført konisering. De samlete samfunnsøkonomiske kostnader ved screeningprogrammet var 730 millioner kroner, hvorav 52 prosent utgjorde indirekte kostnader i form av reisekostnader og fravær fra arbeid. Statens direkte utgifter utgjorde 163 millioner kroner. Konklusjon: Det norske screeningprogrammet for livmorhalskreft har betydelige kostnader, der kvinnenes tids- og reisekostnader og legekonsultasjoner veier mest.

• Pedersen, Kine; Sørbye, Sveinung Wergeland; Burger, Emily; Lönnberg, Stefan & Kristiansen, Ivar Sønbø (2015). Using decision-analytic modeling to isolate interventions that are feasible, efficient and optimal: an application from the Norwegian Cervical Cancer Screening Program. Value in Health. ISSN 1098-3015. 18(8), p. 1088–1097. doi: 10.1016/j.jval.2015.08.003. Full text in Research Archive Show summary

  Background Decision makers often need to simultaneously consider multiple criteria or outcomes when deciding whether to adopt new health interventions. Objectives Using decision analysis within the context of cervical cancer screening in Norway, we aimed to aid decision makers in identifying a subset of relevant strategies that are simultaneously efficient, feasible, and optimal. Methods We developed an age-stratified probabilistic decision tree model following a cohort of women attending primary screening through one screening round. We enumerated detected precancers (i.e., cervical intraepithelial neoplasia of grade 2 or more severe (CIN2+)), colposcopies performed, and monetary costs associated with 10 alternative triage algorithms for women with abnormal cytology results. As efficiency metrics, we calculated incremental cost-effectiveness, and harm-benefit, ratios, defined as the additional costs, or the additional number of colposcopies, per additional CIN2+ detected. We estimated capacity requirements and uncertainty surrounding which strategy is optimal according to the decision rule, involving willingness to pay (monetary or resources consumed per added benefit). Results For ages 25 to 33 years, we eliminated four strategies that did not fall on either efficiency frontier, while one strategy was efficient with respect to both efficiency metrics. Compared with current practice in Norway, two strategies detected more precancers at lower monetary costs, but some required more colposcopies. Similar results were found for women aged 34 to 69 years. Conclusions Improving the effectiveness and efficiency of cervical cancer screening may necessitate additional resources. Although efficient and feasible, both society and individuals must specify their willingness to accept the additional resources and perceived harms required to increase effectiveness before a strategy can be considered optimal.

• Kvamme, Maria Knoph; Lie, Elisabeth; Uhlig, Till; Moger, Tron Anders; Kvien, Tore Kristian & Kristiansen, Ivar Sønbø (2015). Cost-effectiveness of TNF inhibitors vs synthetic disease-modifying antirheumatic drugs in patients with rheumatoid arthritis: A Markov model study based on two longitudinal observational studies. Rheumatology. ISSN 1462-0324. 54(7), p. 1226–1235. doi: 10.1093/rheumatology/keu460. Full text in Research Archive
• Burger, Emily; Sy, Stephen; Nygård, Mari; Kristiansen, Ivar Sønbø & Kim, Jane J (2015). Too late to vaccinate? The incremental benefits and cost-effectiveness of a delayed catch-up program using the 4-valent human papillomavirus vaccine in Norway. Journal of Infectious Diseases. ISSN 0022-1899. 211(2), p. 206–215. doi: 10.1093/infdis/jiu413. Full text in Research Archive Show summary

  Background: Human papillomavirus (HPV) vaccines are ideally administered prior to HPV exposure; therefore catch-up programs for girls past adolescence have not been readily funded. We evaluated the benefits and cost-effectiveness of a delayed, 1-year female catch-up vaccination program in Norway. Methods: We calibrated a dynamic HPV transmission model to Norwegian data and projected the costs and benefits associated with eight HPV-related conditions while varying the upper vaccination age limit to 20, 22, 24 or 26 years. We explored the impact of vaccine protection in women with prior vaccine-targeted HPV infections, vaccine cost, coverage, and natural- and vaccine-induced immunity. Results: The incremental benefits and cost-effectiveness decreased as the upper age limit for catch-up increased. Assuming a vaccine cost of $150/dose, vaccination up to age 20 remained below Norway’s willingness-to-pay threshold (≈$83,000/ quality-adjusted life year gained); extension to age 22 was cost-effective at a lower cost-per-dose ($50-$75). At high levels of vaccine protection in women with prior HPV exposure, vaccinating up to age 26 was cost-effective. Results were stable with lower coverage. Conclusions: HPV vaccination catch-up programs may be warranted five years after routine implementation; however, even at low vaccine cost per dose, the cost-effectiveness of vaccinating beyond age 22 remains uncertain.

• Burger, Emily; Nygård, Mari; Gyrd-Hansen, Dorte; Moger, Tron Anders & Kristiansen, Ivar Sønbø (2014). Does the primary screening test influence women's anxiety and intention to screen for cervical cancer? A randomized survey of Norwegian women. BMC Public Health. 14:360. doi: 10.1186/1471-2458-14-360. Full text in Research Archive Show summary

  Background Countries must decide whether or not to replace primary cytology-based screening with primary human papillomavirus (HPV)-based screening. We aimed to assess how primary screening for an HPV infection, a sexually transmitted infection (STI), and the type of information included in the invitation letter, will affect screening intention. Methods We randomized a representative sample of Norwegian women to one of three invitation letters: 1) Pap smear, 2) HPV testing or 3) HPV testing with additional information about the nature of the infection. Intention to participate, anxiety level and whether women intend to follow-up abnormal results were measured between groups using chi-squared and nonparametric Kruskal-Wallis tests. Determinants of intention were explored using logistic regression. Results Responses from 3540 women were representative of the Norwegian population with respect to age, civil status and geographic location. No significant difference across invitation letters was found in women’s stated intention to participate (range: 91.8-92.3%), anxiety (39-42% were either quite or very worried) or to follow-up after an abnormal result (range: 97.1-97.6%). Strength of intention to participate was only marginally lower for HPV-based invitation letters, albeit significant (p-value?=?0.008), when measured on a scale. Only 36–40% of respondents given the HPV invitations correctly understood that they likely had an STI. Conclusions We found that switching to primary HPV screening, independent of additional information about HPV infections, is not likely to reduce screening participation rates or increase anxiety; however, women lacked the ability to interpret the meaning of an HPV-test result.

• LUNDQVIST, CHRISTOFER; Beiske, Antonie Giæver; Reiertsen, Ola & Kristiansen, Ivar Sønbø (2014). Real life cost and quality of life associated with continuous intraduodenal levodopa infusion compared with oral treatment in Parkinson patients. Journal of Neurology. ISSN 0340-5354. 261(12), p. 2438–2445. doi: 10.1007/s00415-014-7515-4. Full text in Research Archive
• Blasio, Birgitte Freiesleben De; Flem, Elmira; Latipov, Renat; Kuatbaeva, Ajnagul & Kristiansen, Ivar Sønbø (2014). Dynamic Modeling of Cost-effectiveness of Rotavirus Vaccination, Kazakhstan. Emerging Infectious Diseases. ISSN 1080-6040. 20(1), p. 29–37. doi: 10.3201/eid2001.130019. Full text in Research Archive
• Burger, Emily; Sy, Stephen; Nygård, Mari; Kristiansen, Ivar Sønbø & Kim, Jane J (2014). Prevention of HPV-Related Cancers in Norway: Cost-Effectiveness of Expanding the HPV Vaccination Program to Include Pre-Adolescent Boys. PLOS ONE. 9(3), p. e89974–e89974. doi: 10.1371/journal.pone.0089974. Full text in Research Archive Show summary

  Background: Increasingly, countries have introduced female vaccination against human papillomavirus (HPV), causally linked to several cancers and genital warts, but few have recommended vaccination of boys. Declining vaccine prices and strong evidence of vaccine impact on reducing HPV-related conditions in both women and men prompt countries to reevaluate whether HPV vaccination of boys is warranted. Methods: A previously-published dynamic model of HPV transmission was empirically calibrated to Norway. Reductions in the incidence of HPV, including both direct and indirect benefits, were applied to a natural history model of cervical cancer, and to incidence-based models for other non-cervical HPV-related diseases. We calculated the health outcomes and costs of the different HPV-related conditions under a gender-neutral vaccination program compared to a female-only program. Results: Vaccine price had a decisive impact on results. For example, assuming 71% coverage, high vaccine efficacy and a reasonable vaccine tender price of $75 per dose, we found vaccinating both girls and boys fell below a commonly cited cost-effectiveness threshold in Norway ($83,000/quality-adjusted life year (QALY) gained) when including vaccine benefit for all HPV-related diseases. However, at the current market price, including boys would not be considered ‘good value for money.’ For settings with a lower cost-effectiveness threshold ($30,000/QALY), it would not be considered cost-effective to expand the current program to include boys, unless the vaccine price was less than $36/dose. Increasing vaccination coverage to 90% among girls was more effective and less costly than the benefits achieved by vaccinating both genders with 71% coverage. Conclusions: At the anticipated tender price, expanding the HPV vaccination program to boys may be cost-effective and may warrant a change in the current female-only vaccination policy in Norway. However, increasing coverage in girls is uniformly more effective and cost-effective than expanding vaccination coverage to boys and should be considered a priority.

• Bøhmer, Ellen; Kristiansen, Ivar Sønbø; Arnesen, Harald & Halvorsen, Sigrun (2014). Health-related quality of life after myocardial infarction, does choice of method make a difference? Scandinavian Cardiovascular Journal. ISSN 1401-7431. 48(4), p. 216–222. doi: 10.3109/14017431.2014.923581. Full text in Research Archive
• Harmsen, Charlotte G; Kristiansen, Ivar Sønbø; Larsen, Pia Veldt; Nexøe, Jørgen; Støvring, Henrik & Gyrd-Hansen, Dorte [Show all 9 contributors for this article] (2014). Communicating risk using absolute risk reduction or prolongation of life formats: Cluster-randomisedtrial in general practice. British Journal of General Practice. ISSN 0960-1643. 64(621), p. e199–e207. doi: 10.3399/bjgp14X677824. Full text in Research Archive
• Lousdal, Mette L; Kristiansen, Ivar Sønbø; Møller, Bjørn & Støvring, Henrik (2014). Trends in breast cancer stage distribution before, during and after introduction of a screening programme in Norway. European Journal of Public Health. ISSN 1101-1262. 24(6), p. 1017–1022. doi: 10.1093/eurpub/cku015. Full text in Research Archive
• Støvring, Henrik; Harmsen, CG; Wisløff, Torbjørn; Jarbøl, DE; Nexøe, Jørgen & Nielsen, Jesper Bo [Show all 7 contributors for this article] (2013). A competing risk approach for the European Heart SCORE model based on cause-specific and all-cause mortality. European Journal of Preventive Cardiology (EJPC). ISSN 2047-4873. 20(5), p. 827–836. doi: 10.1177/2047487312445425. Full text in Research Archive Show summary

  Background: The European Heart SCORE model constitutes the basis for national guidelines for primary prevention and treatment of cardiovascular disease (CVD) in several European countries. The model estimates individuals’ 10-year CVD mortality risks from age, sex, smoking status, systolic blood pressure, and total cholesterol level. The SCORE model, however, is not mathematically consistent and does not estimate all-cause mortality. Our aim is to modify the SCORE model to allow consistent estimation of both CVD-specific and all-cause mortality. Methods: Using a competing risk approach, we first re-estimated the cause-specific risk of dying from cardiovascular disease, and secondly we incorporated non-CVD mortality. Finally, non-CVD mortality was allowed to also depend on smoking status, and not only age and sex. From the models, we estimated CVD-specific and all-cause 10-year mortality risk, and the expected residual lifetime together with corresponding expected effects of statin treatment. Results: The modified model provided CVD-specific 10-year mortality risks similar to those of the European Heart SCORE model. Incorporation of non-CVD mortality increased 10-year mortality risks, in particular for older individuals. When non-CVD mortality was assumed unaffected by smoking status, the absolute risk reduction due to statin treatment ranged from 0.0% to 3.5%, whereas the gain in expected residual lifetime ranged from 3 to 11 months. Statin effectiveness increased for non-smokers and declined for smokers, when smoking was allowed to influence non-CVD mortality. Conclusion: The modified model provides mathematically consistent estimates of mortality risk and expected residual lifetime together with expected benefits from statin treatment.

• Harmsen, Charlotte G; Jarbøl, Dorte E; Nexøe, Jørgen; Støvring, Henrik; Gyrd-Hansen, Dorte & Nielsen, Jesper Bo [Show all 8 contributors for this article] (2013). Impact of effectiveness information format on patient choice of therapy and satisfaction with decisions about chronic disease medication: the "Influence of intervention Methodologies on Patient Choice of Therapy (IMPACT)" cluster-randomised trial in general practice. BMC Health Services Research. 13. doi: 10.1186/1472-6963-13-76. Full text in Research Archive
• Boberg, Kirsten Muri; Wisløff, Torbjørn; Kjøllesdal, Karl Sæbjørn; Støvring, Henrik & Kristiansen, Ivar Sønbø (2013). Cost and health consequences of treatment of primary biliary cirrhosis with ursodeoxycholic acid. Alimentary Pharmacology and Therapeutics. ISSN 0269-2813. 38(7), p. 794–803. doi: 10.1111/apt.12435. Full text in Research Archive
• Halvorsen, Peder Andreas; Edwards, A.; Aaraas, Ivar Johannes; Aasland, Olaf Gjerløw & Kristiansen, Ivar Sønbø (2013). What professional activities do general practitioners find most meaningful? Cross sectional survey of Norwegian general practitioners. BMC Family Practice. 14(41). doi: 10.1186/1471-2296-14-41. Full text in Research Archive Show summary

  Health reforms in many countries affect the scope and nature of primary care. General Practitioners (GPs) are expected to spend more time developing public health, preventive health care, coordination of care and teamwork. We aimed to explore which professional activities GPs consider to be meaningful and how they would like to prioritise tasks. In a cross sectional online survey 3,270 GPs were invited to consider twenty different activities in general practice. They were asked to rate each of them on a Likert scale anchored from 1 (not meaningful) to 5 (very meaningful). They then selected three activities from the item list on which they would like to spend more time and three activities on which they would like to spend less time. We used multinomial logistic regression to explore associations between the GPs’ preferences for time spent on preventive health care activities and age, gender and practice characteristics. Approximately 40% (n=1,308) responded. The most meaningful activities were handling common symptoms and complaints (94% scored 4 or 5), chronic somatic diseases (93%), terminal care (80%), chronic psychiatric diseases (77%), risk conditions (76%) and on call emergency services (70%). In terms of priority the same items prevailed except that GPs would like to spend less time on emergency services. Items with low priority were health certificates, practice administration, meetings with local health authorities, medically unexplained symptoms, addiction medicine, follow up of people certified unfit for work, psychosocial problems, preventive health clinics for children and school health services. In multivariate regression models physician and practice characteristics explained no more than 10% of the variability in the GPs’ preferences for time spent on preventive health care services. The GPs found diagnosis and treatment of diseases most meaningful. Their priorities were partly at odds with those of the health authorities and policy makers.

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• Pleym, Karin; Engebretsen, Ingrid; Sverre, Elise Christine Bjørkholen; Dammen, Toril; Husebye, Einar & kahlon, Mohpal Singh [Show all 10 contributors for this article] (2026). Cost-effectiveness of in-hospital motivational smoking cessation counselling and proactive referral to community-based follow-up. European Journal of Preventive Cardiology (EJPC). ISSN 2047-4873. 33(Supplement_2). doi: 10.1093/eurjpc/zwag249.265. Full text in Research Archive Show summary

  Abstract Background Hospital-based smoking cessation interventions are generally cost-effective, but most economic evaluations among inpatients with atherosclerotic cardiovascular disease (ASCVD) rely on modelled data only rather than patient-level data (1). Moreover, cost-effectiveness evidence for motivational interviewing in smoking cessation is limited and is primarily derived from non-hospitalised populations (2,3). Purpose To evaluate the cost-effectiveness of an in-hospital smoking cessation intervention with proactive referral to community-based follow-up among patients with ASCVD. Methods We performed an economic evaluation alongside a randomised controlled trial using a hospital perspective. The analysis included the cost of training, materials, and personnel. We recorded survival over sixteen months. Hospital costs during this period were monetised using Diagnosis Related Group cost weights. Survival beyond follow-up was projected using national mortality data adjusted for age, sex, and ASCVD. Remaining lifetime costs were estimated from mean costs in the final six months of follow-up. Costs and life-years were discounted at four percent. Uncertainty was assessed with 2000 bootstrap replicates. The primary outcome was net monetary benefit using a willingness-to-pay threshold of €38,346 per life-year. Results Mean baseline age was 65.2 years. During the sixteen-month follow-up, five participants in the intervention group and nine in the control group died. The intervention group had lower per-patient hospital costs during follow-up (€9,114 versus €13,973; difference: €4,859; 95% confidence interval [CI]: –€1,514 to €11,232). Lifetime costs were higher in the intervention group due to longer projected survival (€114,170 versus €110,522; difference: €3,648; uncertainty estimates [UE]: -€19,816 to €27,718). Undiscounted remaining life expectancy was 20.5 years in the intervention group and 18.7 years in the control group, (difference: 1.7 years, 95% UE: –1.9 to 6.1). The estimated net monetary benefit was €37,475 (95% CI: -15,868 to 107,797) and the probability that the intervention was cost-effective at the €38,346 per life-year threshold was 90.5% (Figure). Conclusion An in-hospital, motivational smoking cessation intervention with proactive referral to community-based support is likely to be cost-effective from a hospital perspective for patients with atherosclerotic vascular disease.FigureFor image description, please refer to the figure legend and surrounding text.

• Aas, Eline; Kinge, Jonas Minet; Burger, Emily Annika; Pedersen, Kine; Iversen, Tor & Godager, Geir [Show all 14 contributors for this article] (2025). Feil tallgrunnlag kan koste liv i helsetjenesten. Full text in Research Archive
• Kristiansen, Ivar Sønbø (2025). Ventetidsløftet – Er det sykehusene som skaper økte helsekøer? Dagens medisin. ISSN 1501-4290. doi: https:/www.dagensmedisin.no/helsepolitikk-og-helseokonomi-ventelister-ventetidsloftet/ventetidsloftet-er-det-sykehusene-som-skaper-okte-helsekoer/695100. Full text in Research Archive Show summary

  Kamp mot helsekøer er et risikabelt politisk prosjekt, fordi pasienter ønsker flere tjenester og helsepersonell ønsker å tilby de beste, trolig mer enn det er kapasitet til på sikt.

• Holly, Teresa; Brun, Marthe Kirkesæther; Jørgensen, Kristin Kaasen; Goll, Guro Løvik; Sexton, Joseph & Gehin, Johanna [Show all 16 contributors for this article] (2025). Cost-effectiveness of proactive therapeutic drug monitoring (TDM) in patients with inflmmatory disease-results from the Nor-Drum trial. Full text in Research Archive
• Engebretsen, Ingrid; Ødegaard, Kristina Malene; Halvorsen, Sigrun; Bugge, Christoffer; Kristiansen, Ivar Sønbø & Støvring, Henrik [Show all 7 contributors for this article] (2024). High discontinuation rate of statins among PCSK9i users: a nationwide study from 2015-2023. European Heart Journal, Supplement. ISSN 1520-765X. 45. doi: 10.1093/eurheartj/ehae666.2863. Full text in Research Archive
• Engebretsen, Ingrid; Ødegaard, Kristina Malene; Halvorsen, Sigrun; Bugge, Christoffer; Kristiansen, Ivar Sønbø & Støvring, Henrik [Show all 7 contributors for this article] (2024). High discontinuation rate of statins among PCSK9i users:A nationwide study from 2015-2023. Full text in Research Archive
• Tyrihjell, Johannes Bjørnstad; Pedersen, Kine; Værnø, Susanne Gerda; Godager, Geir; Sen, Tor Iver & Holte, Jon Helgheim [Show all 11 contributors for this article] (2024). Går vi mot en ny vri på fastlegeordningen? 144(10). doi: 10.4045/tidsskr.24.0339. Full text in Research Archive
• Østby, Jens Torup & Kristiansen, Ivar Sønbø (2023). Hvordan ta hensyn til helsetjenestens verdiskaping ved prioritering av helsetiltak? 143(17). doi: 10.4045/tidsskr.23.0706. Full text in Research Archive
• Syse, Aslak & Kristiansen, Ivar Sønbø (2022). Legers rolle i Nye metoder. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 142(1), p. 1–3. doi: 10.4045/tidsskr.21.0823. Full text in Research Archive
• Zahl, Per Henrik & Kristiansen, Ivar Sønbø (2020). Re: Stage-specific survival has improved for young breast cancer patients since 2000: but not equally? Breast Cancer Research and Treatment. ISSN 0167-6806. 185(2), p. 527–528. doi: 10.1007/s10549-020-05941-7. Full text in Research Archive
• Kristiansen, Ivar Sønbø; Burger, Emily & Blasio, Birgitte Freiesleben De (2020). Covid-19: Simuleringsmodeller ved epidemier. 140(6), p. 1–6. doi: 10.4045/TIDSSKR.20.0225. Full text in Research Archive
• Kristiansen, Ivar Sønbø; Burger, Emily & Blasio, Birgitte Freiesleben De (2020). Covid-19: Simuleringsmodeller ved epidemier. 140(6). doi: 10.4045/tidsskr.20.0225. Full text in Research Archive
• Kvamme, Maria Knoph; Lie, Elisabeth; Uhlig, Till; Moger, Tron Anders; Kvien, Tore Kristian & Kristiansen, Ivar Sønbø (2020). Erratum: Cost-effectiveness of TNF inhibitors vs synthetic disease-modifying antirheumatic drugs in patients with rheumatoid arthritis: A Markov model study based on two longitudinal observational studies (Rheumatology (2015 54 (1226-1235) DOI: 10.1093/rheumatology/keu460). Rheumatology. ISSN 1462-0324. 59(4), p. 917–917. doi: 10.1093/rheumatology/kez609. Full text in Research Archive
• Kristiansen, Ivar Sønbø; Bugge, Christoffer & Førde, Olav Helge (2018). Bidrar overdiagnostikk til høye melanomtall? Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 138(11), p. 1007–1010. doi: 10.4045/tidsskr.17.0600. Full text in Research Archive
• Kristiansen, Ivar Sønbø & Bugge, Christoffer (2018). Prioritering i pasienters siste leveår. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 138(9). doi: 10.4045/tidsskr.18.0389. Full text in Research Archive
• Kristiansen, Ivar Sønbø; Bugge, Christoffer & Førde, Olav Helge (2018). Kristiansen og medarbeidere svarer :. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 138(12), p. 1102–1103. doi: 10.4045/tidsskr.18.0594. Full text in Research Archive
• Burger, Emily; Pedersen, Kine; Sy, Stephen; Kristiansen, Ivar Sønbø & Kim, Jane J. (2017). Primary HPV-based Cervical Cancer Screening: Balancing Health Benefits Colposcopy Referrals. Full text in Research Archive
• Kristiansen, Ivar Sønbø (2017). Verdiløs helsepolitikk. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 137(16), p. 1156–1157. doi: 10.4045/tidsskr.17.0667. Full text in Research Archive
• Hagen, Gunhild; Wisløff, Torbjørn & Kristiansen, Ivar Sønbø (2016). Bør Tine rekruttere melkedrikkere? Aftenposten (morgenutg. : trykt utg.). ISSN 0804-3116. Full text in Research Archive
• Mundal, Liv; Igland, Jannicke; Veierød, Marit Bragelien; Holven, Kirsten Bjørklund; Selmer, Randi & Wisløff, Torbjørn [Show all 8 contributors for this article] (2016). INCIDENCE OF ACUTE MYOCARDIAL INFARCTION IN PATIENTS WITH GENOTYPED FAMILIAL HYPERCHOLESTEROLEMIA IN NORWAY DURING 2001-2009. Circulation. ISSN 0009-7322. 134 (25), p. E711–E711. Full text in Research Archive
• Pedersen, Kine; Burger, Emily; Sy, Stephen; Kristiansen, Ivar Sønbø & Kim, Jane J. (2016). Cost-effective management of women with minor cervical lesions: Revisiting the application of HPV DNA testing. Full text in Research Archive
• Sørbye, Sveinung Wergeland; Kristiansen, Ivar Sønbø; Ursin, Giske; Iversen, Ole-Erik & Aarseth, Hans Petter (2016). Fortsatt strid om etikken bak HPV-prosjekt. [Internet]. Dagens Medisin. Full text in Research Archive Show summary

  Forskere mener pilotprosjektet burde vært søkt Regional Etisk Komite (REK) på vanlig måte, som for andre kliniske studier. – Det at Kreftregisteret har valgt randomisering betyr at det er tvil om effekten av innføringen. Det er usikkert om HPV-test hvert femte år forebygger mer kreft enn celleprøve hvert tredje år. Dersom man velger å randomisere er det per definisjon en studie, sier Sveinung Wergeland Sørbye, overlege i patologi ved Universitetssykehuset i Nord-Norge.

• Pedersen, Kine; Sørbye, Sveinung Wergeland; Burger, Emily; Lönnberg, Stefan & Kristiansen, Ivar Sønbø (2015). Quantifying benefits and harms in cervical cancer screening: A decision analytic approach. Full text in Research Archive
• Pedersen, Kine; Sørbye, Sveinung Wergeland; Kristiansen, Ivar Sønbø & Burger, Emily (2015). Novel Biomarkers to Triage Women with Minor Cervical Lesions: Quantifying the Cost-Effectiveness Tradeoffs to Ensure Feasible Implementation. Full text in Research Archive
• Kristiansen, Ivar Sønbø & Sørbye, Sveinung Wergeland (2014). HPV-testing: Usikkerhet og verdivalg. Full text in Research Archive Show summary

  Vi støtter forslaget om å prøve ut HPV-testing i Norge, men bare dersom forsøket er REK-godkjent og kvinnene er informert om at de deltar i en eksperimentell studie. Alle involverte må få tallmessig informasjon om HPV-testingens positive og negative konsekvenser.

• Sørbye, Sveinung Wergeland & Kristiansen, Ivar Sønbø (2014). - En celleprøve er ikke en perfekt test som kan garantere mot utvikling av livmorhals-kreft. p. 3–3. Full text in Research Archive Show summary

  I Norge har vi et organisert masseundersøkelsesprogram mot livmorhalskreft. Kvinner fra 25–69 år anbefales å ta celleprøve hvert tredje år, og omtrent 80 prosent tar prøven. Det har trolig halvert antallet tilfeller av livmorhalskreft. Hvert år får likevel ca. 300 kvinner påvist denne typen kreft. Omtrent 150 av disse kvinnene har tatt celleprøve og omtrent 70 har hatt bare normale celleprøver.

• Sørbye, Sveinung Wergeland; Stålcrantz, Jeanette; Trovik, Jone; Nøkleby, Hanne & Kristiansen, Ivar Sønbø (2014). - Alle kvinner bør ta denne vaksinen. [Internet]. Klikk.no. Full text in Research Archive Show summary

  Folkehelseinstituttet er ansvarlig for det norske barnevaksinasjonsprogrammet og utgangspunktet deres er at det er viktig at jenter tar HPV-vaksinen før de blir utsatt for smitte slik at de får best mulig effekt av vaksinen. HPV-vaksinen Gardasil er likevel godkjent til bruk hos kvinner opp til 45 år. - At vaksinen bare virker for dem som ikke har vært seksuelt aktive eller har vært smittet er en myte. Det er dokumentert god forebyggende effekt opp til 45 år, sier imidlertid Sveinung Sørbye, overlege ved avdeling for klinisk patologi ved Universitetssykehuset Nord-Norge (UNN), som selv har forelest om vaksinen for andre leger.

• Sørbye, Sveinung Wergeland & Kristiansen, Ivar Sønbø (2014). Forebygging av livmorhalskreft. p. 3–3. Full text in Research Archive Show summary

  Nordlandssykehuset Bodø har blitt omtalt flere ganger i media de siste ukene i forbindelse med at noen kvinner har utviklet kreft i livmorhalsen til tross for at de var undersøkt med celleprøve. Det viste seg i ettertid at flere av prøver som var blitt oppfattet som normale, hadde til dels alvorlige celleforandringer ved fornyet undersøkelse. Saken er politianmeldt og fylkeslegen gransker den. Allmennheten bør vite at celleprøve ikke er en perfekt test som kan garantere mot utvikling av livmorhalskreft.

• Pedersen, Kine; Sørbye, Sveinung Wergeland; Lönnberg, Stefan; Burger, Emily & Kristiansen, Ivar Sønbø (2014). Trade-offs in cervial cancer screening - Balancing detected cancer precursors and resource use. Full text in Research Archive Show summary

  Reflex HPV-testing allows for improvements in both effectiveness and cost-effectiveness of the current screening algorithm. Candidate strategies can detect a larger number of precancers while using fewer resources compared to current practice; however, the optimal strategy depends on society’s willingness to pay costs and accept harms. Ultimately, the down-stream effectiveness of the alternative algorithms will depend on the extent to which precancers regress or progress into cancer.

• Kristiansen, Ivar Sønbø (2014). Re: Hvorfor blir jeg ikke sitert? Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 134(16), p. 1547–1547. doi: 10.4045/tidsskr.14.0915. Full text in Research Archive
• Edwards, Christina Hansen; Tomba, Gianpaolo Scalia; White, Richard Aubrey; Kristiansen, Ivar Sønbø & Blasio, Birgitte Freiesleben de (2014). Dynamic modeling of the cost-effectiveness of sick leave practices during influenza illness. Full text in Research Archive
• Tveito, Marit & Kristiansen, Ivar Sønbø (2014). Tallenes taler. [Journal]. Tidsskrift for Den norske legeforening (Tidsskriftet). doi: 10.4045/tidsskr.13.1638. Full text in Research Archive
• Samuelsen, Carl Haakon; Augestad, Liv Ariane; Stavem, Knut; Kristiansen, Ivar Sønbø & Rand-Hendriksen, Kim (2013). Anchoring effects in the Lead-Time Time Trade-Off. Full text in Research Archive
• Hagen, Gunhild; Rand-Hendriksen, Kim; Bjørnelv, Gudrun Maria Waaler; Kvamme, Maria Knoph & Kristiansen, Ivar Sønbø (2013). Bør prioriteringer QALYfiseres? Full text in Research Archive
• Sørbye, Sveinung Wergeland; Halvorsen, Peder Andreas & Kristiansen, Ivar Sønbø (2013). Screening for livmorhalskreft – fastlegenes viktigste screeningoppgave? Utposten. ISSN 0800-5680. 42(2), p. 34–37. Full text in Research Archive Show summary

  Tidlig på 90-tallet møter ”Eva” til screening for livmorhalskreft. Prøven viser lavgradige celleforandringer. Oppfølging ihht. retningslinjer medfører at ”Eva” de neste 18 årene får utført til sammen 16 nye celleprøver og 7 biopsier. Etter innføring av HPV testing viser celleprøven lavgradige celleforandringer og positiv HPV-test. Biopsi viser nå CIN 2, og ”Eva” blir konisert. Histologisk undersøkelse av resektatet viser invasiv cervixcancer, og ”Eva” blir hysterektomert.

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