Significant reduction in antibiotic prescription rates in Japan following implementation of the national action plan on antimicrobial resistance (2016–20): a 9-year interrupted time-series analysis

Background: Research on the effectiveness of Japan's national action plan on antimicrobial resistance, including among individuals with HIV, remains scarce. Objectives: To evaluate the impact of policies on antibiotic prescription practices. Methods: Outpatient oral antibiotic prescription data from 2012 to 2020 were extracted from a national claims database comprising >98% of the Japanese population. Prescription rates were stratified according to antibiotic class, diagnosis and HIV status. An interrupted time-series analysis was performed to assess the impact of the national action plan. Results: An average of 129,989,400 prescriptions were issued annually (1024 per 1000 population-years). Between 2012 and 2020, the oral antibiotic prescription rate decreased by 54%. The prescription rate showed a significant downward trend post-intervention (additional annual reduction in incidence rate ratio, 0.889; 95% confidence interval, 0.889-0.990). However, broad-spectrum antibiotics (third-generation cephalosporins, macrolides and fluoroquinolones) remained prevalent, comprising 84.7% and 71.4% of prescriptions in 2012 and 2020, respectively. Antibiotic prescriptions during outpatient visits for pharyngitis, sinusitis, bronchitis and viral upper respiratory infections decreased significantly (rate ratios = 0.66, 0.76, 0.51 and 0.49, respectively). The antibiotic prescription rate was ∼2.5-fold higher in individuals with HIV than in those without. Conclusions: Antibiotic prescription rates significantly decreased following the implementation of the national action plan. However, a sharp decline in 2020, likely due to the coronavirus disease pandemic, requires continued rebound monitoring. Reducing broad-spectrum oral antibiotic overuse remains a critical focus.