(B-065) Regional Impact of the COVID-19 Pandemic on Polypharmacy Reduction Policies in Japan: A Nationwide Serial Cross-Sectional Study

Background: Polypharmacy is a serious global health issue, particularly impacting older adults. In Japan, a polypharmacy reduction policy included new incentive of 1,000 JPY (6.4 USD as of Dec 23, 2024) was implemented by Ministry of Health, Labor and Welfare（MHLW) in April 2020 at the same time as the state of emergency for the COVID-19 pandemic in case of documented proposals by pharmacies to inform prescribing physicians of duplicate medications.

Objectives: This study analyzed the impact of the COVID-19 pandemic on the polypharmacy reduction policy.

Methods: A nationwide serial cross-sectional study was conducted using the national database on annual reimbursement claims for outpatient prescription fees in Japan, which covers almost all prescriptions. Polypharmacy was defined as 7 medications or more in same prescription. Polypharmacy proportion (PP) in Japan were calculated as outcome variables to conduct pre-post analysis, with April 2019 – March 2020 as pre-COVID and April 2020 – March 2021 as during-COVID. The analysis was performed at the regional level, dividing the country into 335 units called secondary medical area, based on medical administrative divisions designated by MHLW. The means (95%CI) for PP were analyzed, and a paired t-test was performed for the mean difference between PPs. In addition, multiple linear regression analysis was performed to analyze the five factors (older adults proportion, annual prescription reduction ratio, population density, the number of hospitals, and the number of pharmacists) possibly contributing to the outcome variables. Two-sided p-values less than 0.05 were defined as statistically significant.

Results: In the national level, the mean value of PP (pre-COVID) shows 4.17 (4.05–4.30) and that of PP (during-COVID) shows 4.16 (4.04–4.27), and statistically significant reduction was not observed. Multiple linear regression revealed statistically significant associations between polypharmacy reduction ratio and the proportion of older adults (75 years or above) (p-value 0.022) and the reduction ratio of total annual prescriptions (p-value < 0.001).

Conclusions: The effectiveness of polypharmacy reduction policies during the COVID-19 pandemic was limited in national level. The high older population may promote the effective polypharmacy reduction even during pandemic, and decreased outpatient visits during pandemic might limit the effectiveness of the policies.