OBJECTIVES: To compare all-cause and respiratory-related healthcare resource utilization (HRU) among influenza patients treated with antiviral agents baloxavir marboxil (BALOX) or oseltamivir (OSELT).

METHODS: This observational cohort study used insurance claims data from the U.S. Merative^TM Medicaid database. Patients ³12 years of age, with an outpatient diagnosis of influenza during the 2018-2019 or 2019-2020 seasons who received BALOX or OSELT antiviral treatment within 2 days of diagnosis, and were continuously enrolled ³12 months before and ³30 days after diagnosis were included. BALOX patients were propensity-score matched on baseline characteristics to OSELT patients at a 1:5 ratio. Outcomes were assessed over the 30 days following the antiviral prescription fill in all patients and separately for a subgroup of patients at high risk of flu complications, and included all-cause inpatient admissions, emergency department (ED) visits, outpatient office visits, and outpatient prescription fills.

RESULTS: Matched BALOX or OSELT cohorts included 206/1,030 patients, with mean (SD) age of 25.0 (11.3) /25.0 (12.4) years, respectively; 64.1/66.9% of BALOX/OSELT patients were female. High-risk cohorts included 138/690 patients treated with BALOX or OSELT, with mean (SD) age of 26.4 (11.6)/26.7 (12.8), respectively; 71.0%/72.5% were female. In the full and high-risk BALOX/OSELT cohorts respectively 0.5%/0.9% and 0.7%/1.3% had an all-cause hospitalization. ED visits were numerically lower in the BALOX vs OSELT full cohort (5.3%/9.1%) and significantly lower (5.8%/12.5% [p=0.024]) in the high-risk cohort. The proportions of BALOX/OSELT patients with ³1 outpatient office visit were 37.4%/34.8% in the full cohorts and 41.3%/40.7% of high-risk cohorts. The proportions of BALOX/OSELT patients with ³1 outpatient prescription fill were 51.5%/48.4% in the full cohorts and 60.1%/58.0% in the high-risk cohorts.

CONCLUSIONS: Treatment with BALOX versus OSELT for influenza was associated with significantly lower ED visits in the high-risk cohort and with similar resource use for all other outcomes in the high-risk and full Medicaid cohorts.