Hospital-by-hospital carbapenem use in Japan: a nationwide ecological study

The Japanese healthcare system has been based on universal health coverage since 1961. Nationwide antimicrobial use on a hospital-by-hospital basis has not previously been recorded.

To determine the nationwide distribution of carbapenem use on a hospital-by-hospital basis and to build predictive models using available hospital data from Japan.

An ecological study was conducted using open data released from the Government of Japan. The distribution of days of therapy with carbapenem (per 1000 patient-days) was analysed and predictive models built. The top 1% heavy users by crude distribution and observed-per-predicted ratio distribution were listed and compared. The analysis was conducted in three subcategories stratified by hospital characteristics (tertiary, secondary acute care, and fee-for-service) and among patients in two age groups (16-65 and >65 years).

The median days of therapy in the group aged 16-65 years were 7.24 for tertiary hospitals, 3.28 for secondary acute care hospitals, and 1.42 for fee-for-service hospitals. The median days of therapy of the group aged >65 years were 17.28 for tertiary hospitals, 14.43 for secondary acute care hospitals, and 8.21 for fee-for-service hospitals. For multivariable linear regression analyses, each model selected a different combination of covariates from the potential predictors based on hospital characteristics.

Because a single predictive model was not appropriate for all hospitals, tailored models are needed to identify hospitals that are heavy users of carbapenem. These findings may serve as a reference to support further research on antibiotic use in healthcare and aid future policies.