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

Abstract

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) and adults (≥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 ≤48 hours. Using VAS and accounting for 28-day follow-up resulted in higher QALY gain.

Conclusions: QALY gain owing to oseltamivir is limited compared with other diseases, and its clinical meaningfulness remains to be determined. Further analysis is needed to evaluate whether QALY gain and its impact on ILI treatment cost render oseltamivir cost-effective.

Keywords: EQ-5D; Tamiflu; influenza; quality-adjusted life-years; visual analog scale.