The short-term impact of copayment reductions for government subsidised medicines in Australia.

Background: This study aims to examine the short-term, population-level effects of the 2023 Australian Pharmaceutical Benefits Scheme (PBS) copayment reduction on prescription volume, patients' out-of-pocket (OOP) expenditure, and government contributions.

Research design and methods: We conducted a quasi-experimental study using national data from January 2021 to April 2024. For system-level analysis, we examined all drugs used by general patients, focusing on 252 drugs that were 'above copayment' during 2022-2023. We also performed drug category-specific analyses on six broad groups of drugs. Paired-sample t-tests and segmented regression analyses were used to compare prescription volumes, OOP expenditure, and government contributions before and after the copayment reduction.

Results: The copayment reduction was not associated with significant changes in prescription volumes or government contributions for general patients. However, the copayment reduction led to an immediate, but not gradual, decrease in inflation-adjusted OOP expenditure. Specifically, there was a relative reduction of 26.1% at 15 months post-policy for drugs above the general copayment (95% confidence interval (CI): -34.10, -18.10; p-value < 0.001). Similar immediate declines were observed across the six selected drug categories.

Conclusions: Further research is needed to assess the longer-term effects of copayment reductions, particularly their impact on medication adherence and overall healthcare costs.