(B-066) Impact of the antibiotics management policy and the COVID-19 pandemic on antimicrobial usage in Japan: A nationwide serial cross-sectional study

Background: Misuse and overuse of antimicrobial drugs can cause an acquisition of antimicrobial resistance (AMR), and proper antibiotics use is important to minimize the risk of AMR. The Japanese government was proactive to reduce the antimicrobial usage, and adopted the National Action Plan on AMR in 2016. The Ministry of Health, Labour and Welfare in Japan revised the antibiotics management policy to promote the proper use of antibiotics in April 2020. At the same time, the state of emergency for the COVID-19 pandemic was declared by the prime minister. This state has raised people’s awareness of infectious disease control.

Objectives: To analyze the effectiveness of the revisions of the antibiotics management policy and the impact of the COVID-19 pandemic on antimicrobial usage.

Methods: A nationwide serial cross-sectional study was conducted using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) Open Data, which has annual reimbursement claims for patient prescription fees in Japan. Research periods are FY2019 (April 2019-March 2020) and FY2020 (April 2020-March 2021). Nationwide antimicrobial usage was calculated as Defined Daily Dose per 1,000 inhabitants per day (DID); the World Health Organization defined Defined Daily Dose as a hypothetical average daily maintenance dose in adults for the drug’s main indication. Also, this study analyzes DID in 47 prefectures in FY2019 and FY2020. The means (95% CI) for DID were analyzed, and a paired t-test was performed for the mean difference between DID in FY2019 and FY2020.

Results: Nationwide DID in FY2019 was 13.60. DID in FY2020 was 10.48, and 23.0% decrease from the previous year was observed. The mean (95% CI) of DID based on prefectures (n=47) in FY2019 is 13.5 (12.7-14.3), and the mean (95% CI) of DID in FY2020 is 10.6 (9.9-11.2) (p-value < 0.001).

Conclusions: A significant reduction of nationwide antimicrobial usage was observed after April 2020. Additionally, a statistically significant decrease of prefecture-based DID was observed between FY2019 and FY2020. Therefore, the antibiotics management policy and the COVID-19 pandemic positively affected the reduction of antimicrobial usage.