Impact of Adding Oseltamivir to Usual Care on Quality-Adjusted Life-Years During Influenza-Like Illness

Objectives: The ALIC4E trial has shown that oseltamivir reduces recovery time while increasing the risk of nausea. This secondary analysis of the ALIC4E trial aimed to determine the gain in quality-adjusted life-years (QALYs) associated with adding oseltamivir to usual primary care in patients presenting with influenza-like illness (ILI). Methods: Patients with ILI were recruited during the influenza season (2015-2018) in 15 European countries. Patients were assigned to usual care with or without oseltamivir through stratified randomization (age, severity, comorbidities, and symptom onset). Patients' health status was valued with the EQ-5D and visual analog scale (VAS) for up to 28 days. Average EQ-5D and VAS scores over time were estimated for both treatment groups using one-inflated beta regression in children (-13 years old). QALY gain was calculated as the difference between the groups. Sensitivity analysis considered the value set to convert EQ-5D answers to summary scores and the follow-up period. Results: In adults, oseltamivir gained 0.0006 (95% confidence interval 0.0002-0.0010) QALYs, whereas no statistically significant gain was found in children (14-day follow-up, EQ-5D). QALY gains were statistically significant in patients aged >-65 years, patients without relevant comorbidities, or patients experiencing symptoms for