Marius Andre Korssjøen Skow

• Skow, Marius; Brænd, Anja Maria; Emilsson, Louise; Høye, Sigurd; Straand, Jørund & Fossum, Guro Haugen (2026). Antibiotic treatment for acute sinusitis and subsequent health care use and work absence: a nationwide registry study from Norway. Family Practice. ISSN 0263-2136. 43(2). doi: 10.1093/fampra/cmag001. Full text in Research Archive Show summary

  Background Acute sinusitis is common in general practice. Although typically self-limiting, antibiotics are frequently prescribed despite guideline recommendations to restrict use. It remains unclear whether antibiotic treatment reduces subsequent health care use or work absence. Objective T o assess how initial treatment with or without antibiotics for acute sinusitis is associated with subsequent health care use and work absence, and to compare phenoxymethylpenicillin (PcV) versus other antibiotics. Methods Nationwide registry-based observational cohort study of adults with acute sinusitis (ICPC-2: R75) diagnosed in Norwegian general practice 2012–2019. We compared GP visits, Ear, Nose, and Throat (ENT) specialist visits, repeat antibiotic prescriptions, and sick leave days in antibiotic-treated and untreated episodes. We estimated adjusted differences in outcomes between groups using linear regression (daily outcomes) and negative binomial regression (weekly counts). Results We included 627 211 episodes from 413 449 patients. Antibiotics were prescribed in 59% of episodes; 53% received PcV. During the index week, antibiotic use was associated with 1.7 fewer GP visits, 0.1 fewer ENT visits, and 25.1 more sick leave days per 100 episodes. Corresponding figures for the following 4 weeks were: 0.9 fewer GP contacts, 10.7 fewer sick leave days, and 0.6 more antibiotic prescriptions. PcV was associated with slightly more GP visits and re-prescribing than other antibiotics. Conclusions Acute sinusitis is followed by a short-term increase in health care use and work absence. Initial antibiotic use was associated with modest short-term differences, but no meaningful reduction in overall follow-up. Findings are consistent with recommendations for restrictive prescribing and narrow-spectrum use when appropriate.

• Sætre, Håkon; Skow, Marius Andre Hybbestad; Vik, Ingvild; Høye, Sigurd & Emilsson, Louise (2024). Acute cystitis in men– a nationwide study from primary care: antibiotic prescriptions, risk factors, and complications. British Journal of General Practice Open. 8(2). doi: 10.3399/BJGPO.2023.0207. Full text in Research Archive Show summary

  Background Research on acute cystitis in men is scarce and treatment guidelines differ between countries. Improved antibiotic stewardship is needed. Aim To analyse antibiotic prescriptions and outcomes of Norwegian men diagnosed with cystitis in primary care. Design & setting A nationwide retrospective study was undertaken in primary care in Norway. Method We identified all episodes of acute cystitis in men diagnosed in Norwegian primary care during 2012–2019. Choice of antibiotic (from the Norwegian Prescription Database), treatment failure, re-prescription, and complications were stratified by age, calendar year, and risk factors. We used logistic regression to explore predefined risk factors (diabetes, prostate cancer, benign prostate hyperplasia [BPH], urinary retention, and any cancer) with complications (pyelonephritis, prostatitis, and hospitalisation) and re-prescriptions. Linear regression was used to explore time trends. Results In total, 108 994 individuals contributed 148 635 episodes. Narrow-spectrum antibiotics were first-choice treatment in 71.0% of the episodes (52.5% of all prescriptions were pivmecillinam). More than 75% of the episodes with narrow-spectrum versus 82.2% of broad-spectrum treatment did not lead to any re-prescription or complication. Complications occurred in 1.8% of all episodes (0.5% prostatitis, 0.7% pyelonephritis, and 0.7% hospitalisation). BPH was associated with increased risk of complications and re-prescription. Diabetes was associated with a lower risk of re-prescriptions. Prostate cancer and urinary retention were associated with a lower risk of both complications and re-prescriptions. Conclusion Our results support narrow-spectrum antibiotics as first-line treatment. Risk factor analyses warrants further investigation.

• Christensen, Veronika Storaker; Skow, Marius; Flottorp, Signe A.; Strømme, Hilde; Mdala, Ibrahimu & Vallersnes, Odd Martin (2024). Immediate or delayed trial without catheter in acute urinary retention in males: A systematic review. BJUI Compass. 5(8), p. 846–861. doi: 10.1002/bco2.369. Full text in Research Archive Show summary

  Objective To compare the success of establishing spontaneous micturition following immediate trial without catheter (TWOC) to delayed TWOC in males catheterized for acute urinary retention. Materials and methods In this systematic review, we included studies reporting success rates of immediate TWOC or delayed TWOC (≤30 days) among males ≥18 years of age catheterized for acute urinary retention. We excluded studies on suprapubic catheterization, postoperative/perioperative catheterization and urinary retention related to trauma. We searched the following databases: MEDLINE, Embase, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Open Grey and Clinicaltrials.gov. The search was concluded on 30 November 2022. There were no restrictions on language or publication date. Risk of bias was assessed using the ROB 2.0 and ROBINS-I tools. We did random-effects restricted maximum likelihood model meta-analyses. Certainty of evidence was assessed using GRADE. Results We included 61 studies. In two randomized controlled trials (RCTs), both with some concerns for risk of bias, including in total 174 participants, the relative success rate was 1.22 (95% CI 0.84–1.76) favouring delayed TWOC. In two comparative cohort studies, both with serious risk of bias, including 642 participants, the relative success rate was 1.18 (0.94–1.47) favouring delayed TWOC. One study was excluded from this meta-analysis because of critically low quality. Four studies reporting success rates for cohorts with immediate TWOC, all with serious risk of bias, including 409 participants, had an overall success rate of 47% (29–66). Fifty-two studies reporting success rates for cohorts with delayed TWOC, all with serious risk of bias, including 12 489 participants, had an overall success rate of 53% (49–56). The certainty of the evidence was considered low for the RCTs and very low for the rest. Conclusion There was a limited number of appropriately designed studies addressing the research question directly. The evidence favours neither approach.

• Skow, Marius; Fossum, Guro Haugen; Høye, Sigurd; Straand, Jørund; Emilsson, Louise & Brænd, Anja Maria (2023). Antibiotic treatment of respiratory tract infections in adults in Norwegian general practice. JAC-Antimicrobial Resistance (JAC-AMR). 5(1). doi: 10.1093/jacamr/dlac135. Full text in Research Archive Show summary

  Objectives To analyse the prevalence of respiratory tract infection (RTI) episodes with and without antibiotic prescriptions in adult patients in Norwegian general practice during the period 2012–2019. Methods Observational study linking data from the Norwegian Control and Payment for Health Reimbursements Database and the Norwegian Prescription Database. Episodes of acute RTIs in patients aged 18 years or older were identified and linked to antibiotic prescriptions dispensed within 7 days after diagnosis. We analysed annual infection rates and antibiotic prescription rates and antibiotics prescribed for the different RTI conditions. Results RTI episode rate per 1000 inhabitants was 312 in 2012 and 277 in 2019, but showed no linear trend of change during the study period (P = 0.205). Antibiotic prescription rate decreased from 37% of RTI episodes in 2012 to 23% in 2019 (P < 0.001). The reduction in prescribing was most pronounced for episodes coded with ICPC-2 symptom diagnoses, as well as upper RTIs, influenza, acute bronchitis and sinusitis. Prescriptions for phenoxymethylpenicillin decreased from 178 746 in 2012 to 143 095 in 2019, but increased as proportion of total antibiotic prescriptions from 40% in 2012 to 53% in 2019 (P < 0.001). Conclusions This study demonstrates stable RTI episode rates and reduced antibiotic prescription rates for RTIs for adults in Norwegian general practice 2012–2019. We also observed a shift towards relatively more use of phenoxymethylpenicillin and less broad-spectrum antibiotics. These changes are in line with the aims of the Norwegian strategy against antibiotic resistance.

• Skow, Marius Andre Hybbestad; Fossum, Guro Haugen; Høye, Sigurd; Straand, Jørund; Brænd, Anja Maria & Emilsson, Louise (2023). Hospitalizations and severe complications following acute sinusitis in general practice: a registry-based cohort study. Journal of Antimicrobial Chemotherapy. ISSN 0305-7453. 78(9), p. 2217–2227. doi: 10.1093/jac/dkad227. Full text in Research Archive Show summary

  Objectives To investigate complication rates of acute sinusitis in general practice, and whether antibiotic prescribing had an impact on complication rate. Methods All adult patients diagnosed with sinusitis in Norwegian general practice between 1 July 2012 and 30 June 2019 were included. GP consultation data from the Norwegian Control and Payment for Health Reimbursements Database were linked with antibiotic prescriptions (Norwegian Prescription Database) and hospital admissions (Norwegian Patient Registry). Main outcomes were sinusitis-related hospitalizations and severe complications within 30 days. Logistic regression was used to estimate associations between antibiotic prescriptions, prespecified risk factors, individual GP prescribing quintile, and outcomes. Results A total of 711 069 episodes of acute sinusitis in 415 781 patients were identified. During the study period, both annual episode rate (from 30.2 to 21.2 per 1000 inhabitants) and antibiotic prescription rate (63.3% to 46.5%; P < 0.001) decreased. Yearly hospitalization rate was stable at 10.0 cases per 10 000 sinusitis episodes and the corresponding rate of severe complications was 3.2, with no yearly change (P = 0.765). Antibiotic prescribing was associated with increased risk of hospitalization [adjusted OR 1.8 (95% CI 1.5–2.1)] but not with severe complications. Individual GP prescribing quintile was not associated with any of the outcomes, whereas risk factors such as previous drug abuse, or head injury, skull surgery or malformations, and being immunocompromised were significantly associated with increased risk of both outcomes. Conclusions Severe complications of acute sinusitis were rare and no protective effect of high prescribing practice among GPs was found. Recommendations to further reduce antibiotic prescribing are generally encouraged, except for high-risk groups.

• Farrell, Karen; Tandan, Meera; Santiago, Virginia Hernandez; Gagyor, Ildiko; Brænd, Anja Maria & Skow, Marius [Show all 10 contributors for this article] (2021). Treatment of uncomplicated UTI in males: a systematic review of the literature. British Journal of General Practice Open. 26(2). doi: 10.3399/bjgpopen20X101140. Full text in Research Archive Show summary

  Background Urinary tract infections (UTIs) affect around 20% of the male population in their lifetime. The incidence of UTIs in men in the community is 0.9–2.4 cases per 1000 aged &lt;55 years and 7.7 per 1000 aged ≥85 years. Aim To evaluate the outcomes of randomised controlled trials (RCTs) comparing the effectiveness of different antimicrobial treatments and durations for uncomplicated UTIs in adult males in outpatient settings. Method A systematic literature review of RCTs of adult male patients with an uncomplicated UTI treated with oral antimicrobials in any outpatient setting. The outcomes were symptom resolution within 2 weeks of starting treatment, duration until symptom resolution, clinical cure, bacteriological cure, and frequency of adverse events. Results From the 1052 abstracts screened, three provided sufficient information on outcomes. One study compared trimethoprim-sulfamethoxazole for 14 days (21 males) with 42 days (21 males). Fluoroquinolones were compared in the two other RCTs: lomefloxacin (10 males) with norfloxacin (11 males), and ciprofloxacin for 7 days (19 males) and 14 days (19 males). Combining the results from the three RCTs shows that for 75% males with a UTI (76/101) bacteriological cure was reported at the end of the study. Of the 59 patients receiving a fluoroquinolone, 57 (97%) reported bacteriological and clinical cure within 2 weeks after treatment. Conclusion The evidence available is insufficient to make any recommendations in relation to type and duration of antimicrobial treatment for male UTIs. Sufficiently powered RCTs are needed to identify best treatment type and duration for male UTIs in primary care.

• Skow, Marius Andre Hybbestad; Vik, Ingvild & Høye, Sigurd (2020). Antibiotic switch after treatment with UTI antibiotics in male patients. Infectious Diseases. ISSN 2374-4235. 52(6), p. 405–412. doi: 10.1080/23744235.2020.1736329. Full text in Research Archive Show summary

  Background: There is a lack of evidence on treatment of urinary tract infections (UTIs) in male patients in a primary care setting, and whether narrow-spectrum antibiotics are safe and effective. Objectives: To explore antibiotic switch rates after treatment with UTI antibiotics in men over the last 11 years. Material: We analysed data from the Norwegian Prescription Database (NorPD). Men ≥16 years receiving cefalexin, ciprofloxacin, cotrimoxazole, nitrofurantoin, ofloxacin, pivmecillinam or trimethoprim during the period 2008–2018 were included. Antibiotic switch was defined as being prescribed a different antibiotic drug appropriate for UTI within 14 days after initial treatment. We calculated rates of antibiotic switch and corresponding odds ratios for each antibiotic drug. Results: Seven hundred twenty-six thousand and ninety-six (726,096) prescriptions to 429,807 men were defined as possible UTI episodes. Fluoroquinolones, pivmecillinam and cotrimoxazole were most frequently prescribed. Forty-nine thousand five hundred and thirty-one (49,531) (6.8%) of the treatments resulted in antibiotic switch. Compared to cotrimoxazole, the risk of antibiotic switch was higher for pivmecillinam (OR: 2.46; 95% CI, 2.39–2.53) and trimethoprim (OR: 2.12; 95% CI, 2.04–2.20), and lower for fluoroquinolones (OR: 0.40; 95% CI, 0.39–0.42) and cefalexin (OR: 0.28; 95% CI, 0.26–0.30). Treatment duration of ≥7 days and age of ≥50 years were associated with an increased risk of antibiotic switch. Conclusion: Fluoroquinolones and cefalexin were associated with lower antibiotic switch rates than the recommended UTI antibiotics (pivmecillinam, nitrofurantoin and trimethoprim). However, the rates of antibiotic switch following treatment of male patients with first-line empirical UTI antibiotics are relatively low, indicating that the current guidelines are safe.

• Skow, Marius Andre Hybbestad; Bergmann, Natasha & Knop, Filip K. (2016). Diabetes and obesity treatment based on dual incretin receptor activation: ‘twincretins’. Diabetes, obesity and metabolism. ISSN 1462-8902. doi: 10.1111/dom.12685. Full text in Research Archive Show summary

  The gut incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are secreted after meal ingestion and work in concert to promote postprandial insulin secretion and regulate glucagon secretion. GLP-1 also slows gastric emptying and suppresses appetite, whereas GIP seems to affect lipid metabolism. The introduction of selective GLP-1 receptor (GLP-1R) agonists for the treatment of type 2 diabetes and obesity has increased the scientific and clinical interest in incretins. Combining the body weight-lowering and glucose-lowering effects of GLP-1 with a more potent improvement of β cell function through additional GIP action could potentially offer a more effective treatment of diabetes and obesity, with fewer adverse effects than selective GLP-1R agonists; therefore, new drugs designed to co-activate both the GIP receptor (GIPR) and the GLP-1R simultaneously are under development. In the present review, we address advances in the field of GIPR and GLP-1R co-agonism and review in vitro studies, animal studies and human trials involving co-administration of the two incretins, as well as results from a recently developed GIPR/GLP-1R co-agonist, and highlight promising areas and challenges within the field of incretin dual agonists.

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• Renaa, Therese; Fossum, Guro Haugen; Høye, Sigurd; Skow, Marius & Emilsson, Louise (2026). Rate of otitis complications with lower antibiotic prescribing to preschool children in general practice. Nordic Congress of General Practice : Abstracts. Full text in Research Archive Show summary

  Introduction Antibiotic prescribing for otitis decreased in Norway from 2012 to 2019. Diagnosing otitis in young children is challenging, and the consistently high antibiotic prescription rate indicates a low threshold for antibiotic treatment in general practice, likely driven by diagnostic uncertainty and concern for complications. Aim To investigate if the rate of severe complications increases when fewer children with otitis are treated with antibiotics. Methods Registry study based on population data combined from four different health registries: KUHR (The Norwegian control and reimbursement registry), SSB (Norwegian statistics), NPR (The National Patient Registry), and NorPD (the Norwegian prescription registry). Multivariate logistic regressions tested associations of antibiotic treatment for otitis with hospitalization and severe complications, adjusted for demographic factors, underlying illness, health care access and the general practitioners (GP’s) prescription patterns. Severe complications included sinus venous thrombosis, mastoiditis, pneumonia, meningitis and sepsis. Results Preliminary results indicated that of 269,003 otitis episodes, only 300 resulted in a severe complication, 0.1%. Pneumonia and mastoiditis were the most common severe complications. The rate of severe complications changed minimally from 2012 (9/10 000 episodes) to 2019 (11/10 000 episodes), while the antibiotic prescription rate decreased by 21%. Asthma (OR 2.05 CI 1.54 – 2.75) and Down syndrome/craniofacial anomaly (OR 2,63 CI 1.08 – 6.40) gave the highest OR for severe complications among pre-existing conditions. The risk of complications was the same for children treated by low-prescribing GPs as high-prescribing GP’s. Conclusions and clinical implication Severe complications of otitis are rare. There was observed no increase in the rate of complications with lower antibiotic prescription.

• Lindberg, Bent Håkan; Skow, Marius & Høye, Sigurd (2025). Point-of-care white blood cell count – a tool for improved antibiotic prescribing? Full text in Research Archive
• Skow, Marius; Emilsson, Louise; Høye, Sigurd; Straand, Jørund; Brænd, Anja Maria & Fossum, Guro Haugen (2024). BIHULEBETENNELSE I ALLMENNPRAKSIS: PÅVIRKER ANTIBIOTIKA RISIKOEN FOR LANGVARIGE OG KOMPLISERTE PASIENTFORLØP? Full text in Research Archive Show summary

  Bakgrunn: Akutt bihulebetennelse er en vanlig tilstand i allmennpraksis, hvor antibiotika ofte foreskrives, til tross for økende dokumentasjon som viser at ukompliserte tilfeller sjelden har nytte av slik behandling. Risikoen for alvorlige komplikasjoner er lav, og tidligere studier fra norsk allmennpraksis har ikke vist noen vesentlig beskyttende effekt av antibiotika når det gjelder å forhindre sykehusinnleggelser eller alvorlige komplikasjoner etter akutt bihulebetennelse. Denne studien fokuserer på såkalte milde komplikasjoner av akutt bihulebetennelse, med vekt på antall konsultasjoner i allmennpraksis, bruk av spesialisthelsetjenester, sykefravær og antibiotikabruk. Målet med studien er å undersøke forekomsten av forlengede og kompliserte pasientforløp ved akutt bihulebetennelse som behandles utenfor sykehus, og å sammenligne utfallet blant pasienter som behandles med antibiotika, med de som ikke gjør det. Metode: Ved å koble data fra flere nasjonale helseregistre, analyserer vi episoder av akutt bihulebetennelse hos voksne pasienter diagnostisert i allmennpraksis i perioden 2012–2019. For hver episode samler vi inn opplysninger om antibiotikaresepter, legekonsultasjoner, sykemeldinger og kontakter hos øre-nese-hals-spesialister og poliklinikker. Vi bruker en «difference-in-difference»-metode for å sammenligne utfallet av episoder behandlet med og uten antibiotika, ved å undersøke forekomsten av de ulike utfallsmålene i 12 uker etter en akutt bihulebetennelsesepisode, sammenlignet med 12 uker før episoden. Resultater: Vår kohort består over 600 000 episoder av akutt bihulebetennelse. Analysene er ikke ferdige på tidspunktet for innsending av sammendraget, men foreløpige resultater vil bli presentert på møtet. Konklusjoner: Konklusjonene er foreløpig ikke klare og vil bli trukket basert på den endelige analysen av våre data.

• Skow, Marius Andre Hybbestad; Brænd, Anja Maria; Emilsson, Louise; Høye, Sigurd; Straand, Jørund & Fossum, Guro Haugen (2024). Complicated courses of sinusitis in general practice in an era of antibiotic stewardship. Full text in Research Archive
• Skow, Marius; Emilsson, Louise; Straand, Jørund; Høye, Sigurd & Fossum, Guro Haugen (2024). Complicated courses of sinusitis in general practice in an era of antibiotic stewardship. Full text in Research Archive
• Vallersnes, Odd Martin; Skow, Marius; Christensen, Veronika S & Flottorp, Signe Agnes (2024). Engangskateterisering ved urinretensjon. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 144(8), p. 1–3. doi: 10.4045/tidsskr.24.0278. Full text in Research Archive
• Christensen, Veronika S; Skow, Marius; Flottorp, Signe Agnes; Strømme, Hilde; Mdala, Ibrahimu & Vallersnes, Odd Martin (2023). Trial without catheter immediately or after some days when treating acute urinary retention in males: a systematic review. Full text in Research Archive
• Renaa, Therese; Emilsson, Louise; Skow, Marius; Høye, Sigurd & Fossum, Guro Haugen (2023). Antibiotic prescriptions to preschool children with respiratory tract infections in Norwegian primary health care 2012-2019. Full text in Research Archive
• Skow, Marius; Fossum, Guro Haugen; Høye, Sigurd; Straand, Jørund; Brænd, Anja Maria & Emilsson, Louise (2023). Luftveisinfeksjoner og antibiotikaforskrivning i allmennpraksis. Full text in Research Archive
• Christensen, Veronika S; Skow, Marius; Flottorp, Signe Agnes; Strømme, Hilde; Mdala, Ibrahimu & Vallersnes, Odd Martin (2023). Immediate or delayed trial without catheter when treating acute urinary retention in males: a systematic review. Full text in Research Archive
• Christensen, Veronika S; Vallersnes, Odd Martin; Skow, Marius; Strømme, Hilde & Flottorp, Signe Agnes (2022). Trial without catheter immediately or after some days when treating acute urinary retention in males: a systematic review. Full text in Research Archive
• Skow, Marius; Fossum, Guro Haugen; Høye, Sigurd; Straand, Jørund; Emilsson, Louise & Brænd, Anja Maria (2022). Antibiotic treatment of adult patients with respiratory tract infections in Norwegian general practice: A nationwide registry-based study. Full text in Research Archive
• Skow, Marius (2026). Acute Sinusitis in General Practice: Antibiotic Prescribing, Complications, and Patient Trajectories. Universitetet i Oslo. ISSN 9788234808494. Full text in Research Archive Show summary

  Acute sinusitis is one of the most common infections managed in general practice and a leading reason for antibiotic prescribing. Reducing unnecessary antibiotic use is a key public health priority due to the increasing threat of antimicrobial resistance. The aims of this thesis were to examine trends in antibiotic prescribing for acute sinusitis and other respiratory tract infections in Norwegian general practice, to assess whether reduced prescribing was associated with increased rates of serious complications, and to evaluate the impact of antibiotic treatment on subsequent healthcare utilisation and sickness absence. Three register-based studies were conducted using nationwide data from national health registries covering more than nine million respiratory tract infection episodes between 2012 and 2019. Antibiotic prescribing for respiratory tract infections, including sinusitis, declined substantially over the study period, suggesting that national stewardship efforts translated into measurable change in clinical practice. Severe complications following acute sinusitis were rare, and complication rates at the population level did not increase despite the marked reduction in antibiotic prescribing. Antibiotic treatment was associated with only modest differences in subsequent healthcare use and sickness absence, indicating a limited downstream benefit of routine treatment. Overall, the findings suggest that restrictive antibiotic prescribing for acute sinusitis is compatible with safe patient care, and provide real-world support for continued stewardship efforts in primary care.

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