Impact of Patient's Financial Burden of COVID-19 Treatment on Antiviral Prescription Rates, and Clinical and Economic Outcomes in Japan

OBJECTIVES: In Japan, out of pocket (OOP) payment for COVID-19 antiviral drugs was fully covered by public funds until the end of September 2023. The public support was stepwise reduced and completely ended in March 2024. This study aims to evaluate the potential clinical and economic impact of decreased prescription rates of oral antivirals that might result from the OOP payment initiation.

METHODS: To assess the potential impact of OOP changes on the prescription rates of antiviral drugs, we compared prescribing data from two 4-month periods: June–September 2023 (the pre-initiation period of OOP payment) and October 2023–January 2024 (the post-initiation period of OOP payment), using a claims database provided by JMDC Inc. A budget impact analysis (BIA) model was then developed to assess the impacts of hypothetical declines in the prescription rates on COVID-19-related hospitalizations, deaths and direct medical costs for antiviral prescription and hospitalization.

RESULTS: A total of 1,349,149 individuals with definite COVID-19 diagnosis were included in the analysis using the claims database. The proportion of patients with a COVID-19 antiviral prescription in Japan was estimated to be 17.5% and 11.5% in the pre- and post-initiation periods respectively, indicating a 34.3% decrease in the prescription rate of antivirals. The BIA estimated that, assuming a 34.3%, 51.5% (34.3%*1.5) and 77.2% (34.3%*1.5^2) decrease in the prescription rate, the annual number of hospitalizations would increase by 35,390 (3.0%), 53,085 (4.4%), and 79,628 (6.7%), respectively, and the annual net cost for antiviral prescription and hospitalization would increase by JPY 32.1 billion (USD 227.0 million; 1.3%), JPY 48.2 billion (USD 340.5 million; 1.9%), and JPY 72.3 billion (USD 510.7 million; 2.9%), respectively.

CONCLUSIONS: The OOP payment initiation for COVID-19 treatment decreased the antiviral prescription rate, potentially leading to clinical and economic losses in Japan.