Impact of antimicrobial resistance measures and the emergence of COVID-19 on antimicrobial use throughout the Japanese population: A retrospective cohort study using a national claims database

Objective This study examined the impact of Japan’s National Action Plan on Antimicrobial Resistance (NAP) and the COVID-19 pandemic on national trends in antimicrobial consumption (AMC) for major infectious diseases.

This retrospective cohort study analyzed claims data for the Japanese population from 2013 to 2020. AMC was expressed as defined daily doses per 1,000 inhabitants per day. The target diseases included upper respiratory infection (URI), otitis media, pneumonia, diarrhea, urinary tract infection, skin and soft tissue infection, and sexually transmitted infection. Seasonally adjusted interrupted time-series analyses were conducted to assess the impact of NAP publication in 2016 and the COVID-19 outbreak in 2020 on the numbers of medically attended cases and antimicrobial prescription rates.

Total AMC declined from 2016 to 2019, and decreased further in 2020. There was a significant decrease in medically attended cases in 2020 when compared to the counterfactual scenario in which COVID-19 did not occur. AMC was positively correlated with the number of medically attended cases. Total antimicrobial prescription rates decreased after NAP publication and the COVID-19 outbreak. Among the diseases, prescription rates for URI, otitis media, and pneumonia significantly decreased after both events. However, the prescription rate for diarrhea decreased after NAP publication but increased after COVID-19. No significant trends were detected for other diseases.

Antimicrobial prescriptions for respiratory infections steadily decreased after NAP publication, which may indicate the effects of antimicrobial stewardship activities. Continued monitoring is needed to clarify the long-term effects of the COVID-19 pandemic on antimicrobial use. Competing Interest Statement The authors have declared no competing interest. Funding Statement This study was supported by a Ministry of Health, Labour and Welfare Research Grant (23HA2002). Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the Ethics Committee of the National Center for Global Health and Medicine Hospital (NCGM-G-003098-02). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability Data from this study cannot be shared due to legal and administrative restrictions. Data may be directly acquired from the Ministry of Health, Labour and Welfare of Japan for researchers who meet the criteria for access to confidential data. Please contact the corresponding author for further information.