Effectiveness of Oseltamivir in reducing 30-day readmissions and mortality among patients with severe seasonal influenza in Australian hospitalized patients.

BACKGROUND

Worldwide, seasonal influenza causes significant mortality and poses a significant economic burden. Oseltamivir is an effective treatment, but benefits beyond immediate hospitalization are unknown.

METHODS

This retrospective multicenter study included adult hospitalized influenza patients from two major teaching hospitals in Australia. Patients who received Oseltamivir <48 h of admission (prompt-treatment group) were compared with those who either did not receive treatment or if treatment was delayed by >48 h (delayed/no-treatment group). Propensity-score matching was used to balance confounders between two groups. Primary outcomes included 30-day readmissions, 30-day mortality, composite-outcome (30-day mortality and readmissions), in-hospital mortality, and hospital length of stay (LOS).

RESULTS

Between January 2016-March 2020, 1828 adult patients mean (SD) age 66.4 (20.1), 52.9% females, were hospitalized with influenza. Four hundred and forty-eight (24.5%) received prompt-treatment with Oseltamivir, while 1380 (75.5%) patients were in the delayed/no-treatment group. The median (IQR) time from onset of symptoms to the administration of Oseltamivir was three (1-5) days. The propensity-score model included 245 matched patients in each group (standardized mean difference of <10%). Both 30-day readmissions and the composite-outcome were, respectively, 5.7% (P = 0.03) and 6.5% (P = 0.02) lower in patients who received prompt-treatment with Oseltamivir when compared to the delayed/no-treatment group. LOS showed a significant reduction, and in-hospital mortality showed a trend towards improvement among patients who received prompt-treatment when compared to the other group.

CONCLUSIONS

Early administration of Oseltamivir was associated with a reduction in 30-days readmissions and composite-outcome of 30-day readmissions and mortality in adult hospitalized influenza patients when compared to delayed/no-treatment.