Oseltamivir Prescribing Practices for Influenza in Patients in the Intensive Care Unit and Associated Outcomes

Abstract

Specific Aims: To assess appropriateness of prescribing practices of oseltamivir to package insert recommendations and identify significant differences in length of intensive care unit (ICU) stay, length of mechanical ventilation, and mortality in critically ill patients with influenza who received oseltamivir within 48 hours of symptom onset compared to those who did not. Methods: Patients were included in this retrospective, Institutional Review Board (IRB)-approved chart review if they were at least 18 years old with confirmed diagnosis of influenza in an intensive care unit at Banner University Medical Center – Tucson from 2015-2016. Categorical data were analyzed using Fisher’s exact test. Continuous variables were analyzed using a two-sample T-test assuming equal variances. The alpha priori level was 0.05. Main Results: All patients with confirmed influenza were treated with oseltamivir. 52% of patients received oseltamivir within 48 hours of symptom onset and 55% received an appropriate dose based on renal function. 30% of patients received oseltamivir for the recommended 5-day duration. Oseltamivir was prescribed with correct onset, dose, and duration based on package insert recommendations in only 3 instances (9.1%). No difference was seen in ICU length of stay (p = 0.67), hours on mechanical ventilation (p = 0.41), or mortality (p = 0.34) in those patients who received oseltamivir within 48 hours of symptom onset versus those who did not. Conclusions: High variation existed in observed oseltamivir prescribing practices. Future studies should incorporate multiple influenza seasons to permit a larger sample size and involve multiple facilities to allow for greater generalizability.