Trends in healthcare visits and antimicrobial prescriptions for acute infectious diarrhea in individuals aged 65 years or younger in Japan from 2013 to 2018 based on administrative claims database: a retrospective observational study

BACKGROUND: The inappropriate use of antimicrobials for acute infectious diarrhea is widespread and leads to the problem of antimicrobial resistance. To improve the use of antimicrobials, it is first necessary to understand the actual situation of diarrheal disease and to identify potential targets for intervention. This study aimed to investigate the recent epidemiological characteristics of and antimicrobial prescriptions for acute infectious diarrhea in Japan. METHODS: This was a retrospective observational study of outpatients aged 0–65 years, separated into children (age 0–17 years) and adults (age 18–65 years), diagnosed with acute infectious diarrhea, using the administrative claims database of the Japan Medical Data Center from 2013 to 2018. We evaluated the number of eligible visits/number of database registrants (defined as the visit rate). The analysis of the antimicrobial prescription rate was restricted to otherwise healthy individuals diagnosed with acute infectious diarrhea alone by excluding patients with multiple disease diagnoses and with medical backgrounds of chronic bowel diseases or immunocompromised conditions. We further classified them by diagnosis of bacterial or nonbacterial acute infectious diarrhea. RESULTS: The total number of eligible visits for acute infectious diarrhea was 2,600,065. The visit rate, calculated based on the number of eligible visits by database registrants, was higher in children (boys, 0.264; girls, 0.229) than in adults (men, 0.070; women, 0.079), with peaks in early summer and winter. The peaks for visits in adults lagged those of children. In total, 482,484 visits were analyzed to determine the antimicrobial prescription rate; 456,655 (94.6%) were diagnosed with nonbacterial acute infectious diarrhea. Compared with children (boys, 0.305; girls, 0.304), the antimicrobial prescription rate was higher in adults, and there were differences between sexes in adults (men, 0.465; women, 0.408). Fosfomycin and fluoroquinolone were most frequently used for nonbacterial acute infectious diarrhea in children (44.1%) and adults (50.3%), respectively. CONCLUSIONS: These results revealed overprescription of antimicrobials for acute infectious diarrhea in this administrative claims database in Japan and contribute to the development of antimicrobial stewardship strategies and the identification of targets for efficiently reducing inappropriate antimicrobial use. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12879-021-06688-2.