Oseltamivir Has No Benefit for Non-ICU Hospitalised Patients with Seasonal Influenza

Abstract

Background: The effect of treatment with oseltamivir in hospitalised patients with seasonal influenza is unclear. Most available data are obtained from pandemic influenza or the ambulatory setting. Methods: We retrospectively reviewed medical records of two similar hospitals with different Influenza treatment policies. Hospital A had a liberal policy towards treatment with Oseltamivir, while hospital B was rather conservative in its approach. We compared the outcomes of patients treated in the two hospitals (treatment strategy) and the outcome of Oseltamivir vs. only symptomatic treatment (effect of Oseltamivir). Primary endpoints were length of stay (LOS) and duration of fever. Secondary endpoints were 30-day mortality, secondary bacterial pneumonia, secondary transfer to ICU and 30-day rehospitalisation. Patients were stratified for gender, age, DM, coronary heart disease, congestive heart failure, oxygen saturation on admission, COPD, renal failure, immunosuppression, malignancy and Charlson comorbidity Index. Patients directly admitted to ICU were excluded from the analysis. We compared Hospital A with Hospital B and Oseltamivir treated with symptomatically treated patients using a Mann Whitney-U-Test, students t-test and logistic regression. Results: 534 patients were analysed. 280/534 patients had Influenza A, 254/534 Influenza B. 304 were admitted to Hospital A and 230 to Hospital B. 298/534 patients presented within <48 hours of symptom onset. Overall, 199/534 patients received Oseltamivir. Baseline characteristics were not different between patients in Hospital A vs Hospital B, or Oseltamivir treated vs non-antiviral treated patients (p= n.s.). Significantly more patients in Hospital A received Oseltamivir (54.1 vs 15.3%, OR 3.57, CI 2.3-5.48; p<0.001). No differences were seen between the two hospitals in either primary (LOS: 6.5 vs 7.0 days, p=0.82/ fever days 0 vs 1 days, p=0.0.6) or in secondary endpoints. Mortality was 5.5 vs 3.5 % p=0.25. When comparing Oseltamivir treated vs non-antiviral treated patients, no differences in primary or secondary endpoints were observed. LOS was 7 vs 6 days, p=0.64, Duration of fever 1 vs 0 days, p=0.054, and mortality 4.5 vs 4.8 %, p=0.89. Conclusion: In this real life study with non-ICU patients hospitalised with seasonal influenza, treatment with Oseltamivir did not result in an improved outcome. Funding Statement: No funding. Declaration of Interests: All authors report no conflict. Ethics Approval Statement: After approval by the ethics committee (EKNZ 2019_00614) we conducted a retrospective study using the hospital based electronic medical database system (KISIM®) developed by Cistec™.