Prescribed daily-dose-based metrics of oral antibiotic use for hospitalized children in Japan.

Objective: Defined daily-dose (DDD)-based metrics are frequently used to measure antibiotic consumption. However, they are unsuitable for the pediatric population because they are defined using the maintenance dose for 70-kg adults. Moreover, children have large body weight variations. We assessed the prescribed daily dose (PDD) and PDD-based metrics of oral antibiotics for children to develop an alternative to DDD-based metrics in Japan. Design: We performed observational study using data from the Japanese administrative claims database between April 2018 and March 2019. Methods: Of 453,001 patients (aged 1 month-15 years), 564,326 admissions to 1,159 hospitals were included. We showed the median PDD (mg/day and mg/kg/day) and PDD-based metrics for 8 antibiotics for each age category (1 month to <1 year old and 1-6, 7-12, and 13-15 years old). We also assessed the relationship between PDD-based metrics and days of therapy (DOT)-based metrics using a scatter plot and correlation. Results: In total, 86,389 patients (19.1%) were prescribed oral antibiotics; amoxicillin, macrolides, and third-generation cephalosporins were the most common. The PDD (mg/day) for each antibiotic increased with age to 7-12 years old, when an adult dose was reached. The PDD (mg/kg/day) decreased with age to 13-15 years old, due to increasing body weight. The relationship between PDD per 1,000 patient days and DOT per 1,000 patient days differed depending on the antibiotic. Conclusions: PDD-based metrics stratified by age could characterize antibiotic consumption, even with body-weight variations. Therefore, PDD-based metrics, in addition to DOT-based metrics, are helpful benchmarks for antibiotic use in children.