Impact Assessment of an Antimicrobial Stewardship Program in a Japanese University Dental Hospital

Antimicrobial resistance (AMR) due to inappropriate antimicrobial use (AMU) is a significant global concern. In dentistry, antimicrobials are commonly prescribed in large scale in dental outpatient settings. The aim of this study was to evaluate and compare the effectiveness of antimicrobial stewardship programs (ASPs) in a such dental hospital setting in Japan, using an interrupted time-series analyses.

Monthly summarized data from medical records of all outpatients who received oral antimicrobials at the dental university hospital in Kanagawa Prefecture in Japan were evaluated. We compared time trends for the number of days of therapy (DOT), the number of long-term antimicrobial prescription cases, and the proportion of inappropriate long-term AMU, during the periods before (November 2017 to March 2019) and after (April 2019 to August 2021) the ASP introduction.

Following the introduction of the ASP, the mean DOT decreased by approximately 4.4 days (P < .001), although the decline began before program implementation. The actual number of long-term AMU cases was 13 fewer than the predicted 38 per month (95% CI: -25 to -2, P = .027), and the proportion of inappropriate long-term AMU decreased by 23.1% (95% CI: -37.6% to -8.7%, P = .002). These trends persisted for up to 2 years post-ASP implementation.

The introduction of the ASP significantly reduced the number of long-term oral antimicrobial prescriptions and the proportion of inappropriate long-term AMU in outpatient dental care. However, the inappropriate use rate remained a concern at 27.8%, indicating the necessity for maintenance of sustained ASPs. The objectives outlined in the Global Action Plan (2015) by the World Health Organization (WHO) and Japan's National Action Plan (2016-2020) on AMR seem t to have been under achieved. Thus, the promotion of ASPs must be advanced globally both in the medical and dental healthcare facilities.