Obesity in Recovery From Influenza‐Like Illness and Effectiveness of Oseltamivir

ABSTRACT Background Results from observational studies have shown that obesity has a mild to moderate association with influenza‐like illness (ILI) severity and hospitalization risk. Using data from the ALIC 4 E Randomized Clinical Trial (RCT), this study investigated the relationship between obesity and ILI severity, time to recovery, and oseltamivir effectiveness in the obese population. Methods A total of 2622 adults (≥ 18 years old) from the ALIC 4 E RCT were categorized by body mass index (BMI) into under/normal weight (BMI < 25 kg/m 2 ), overweight (BMI ≥ 25 kg/m 2 and < 30 kg/m 2 ), and obesity (BMI ≥ 30 kg/m 2 ). ILI symptom severity, time to recovery, and oseltamivir effectiveness were assessed across these weight groups. Results At presentation, ILI symptom severity was not different between weight groups. However, time to recovery was longer for obese patients compared to under/normal weight patients, with adjusted HR 0.88 (95% CI 0.79–0.99). The mean time to recovery was 6.6 days (95% CI 6.0–7.1) for obese patients, 6.2 days (95% CI 5.8–6.6) for overweight, and 5.7 days (95% CI 5.4–6.1) for under/normal weight patients. Obese patients had similar benefits from oseltamivir treatment compared to under/normal weight patients, with an average of 0.8 days gained from oseltamivir (95% CI 0.7–1) and 0.5 days (95% CI 0.4–0.7), respectively. Conclusions ILI symptom severity at presentation was equally distributed between the three weight groups. However, their time to recovery was approximately 1 day longer compared to under/normal weight patients. The effectiveness of oseltamivir appears to be similar between the two groups.