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.