Burden of Antimicrobial Resistance in Japan: A Systematic Literature Review and Meta-Analysis

Introduction: Antimicrobial resistance (AMR) is one of the most serious public health challenges worldwide, including in Japan. However, there is limited evidence assessing the AMR burden in Japan. Thus, this systematic literature review (SLR) and meta-analysis (MA) were conducted to assess the clinical and economic burden of AMR in Japan. Methods: Comprehensive literature searches were performed on EMBASE, MEDLINE, the Cochrane Library, and ICHUSHI between 2012 and 2022 following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. MA estimated a pooled effect between the two comparative arms (AMR vs. non-AMR). The results were reported in measures of odds ratios (ORs) for in-hospital mortality and in standardized mean differences (SMDs) for length of stay (LOS) and direct medical costs. Results: Literature searches identified 1256 de-duplicated records, of which 56 observational studies (English, n = 35; Japanese, n = 21) were included. Of note, twenty-two studies (39.3%) compared the AMR group with non-AMR group. In the SLR, in-hospital mortality, LOS, and direct medical costs were higher in the AMR group compared to the non-AMR group. Eight studies were selected for the MA. In the AMR group, the pooled estimate showed a statistically higher in-hospital mortality [random effect (RE)—OR 2.25, 95% CI 1.34–3.79; I² = 89%; τ² = 0.2257, p < 0.01], LOS (RE—SMD 0.37, 95% CI − 0.09–0.84; I² = 99%; τ² = 0.3600, p < 0.01), and direct medical cost (RE—SMD 0.53, 95% CI 0.43–0.62; I² = 0.0%; τ² = 0.0, p = 0.88) versus the non-AMR group. Conclusion: Our study presents an overview of the clinical and economic burden of AMR in Japan. Patients with AMR infections experience significantly higher in-hospital mortality, LOS, and direct medical costs compared with patients without AMR infections.