Prevalence and changes of low-value care at acute care hospitals: a multicentre observational study in Japan.

Objectives: We aimed to examine the use and factors associated with the provision of low-value care in Japan.

Design: A multicentre observational study.

Setting: Routinely collected claims data that include all inpatient and outpatient visits in 242 large acute care hospitals (accounting for approximately 11% of all acute hospitalisations in Japan).

Participants: 345 564 patients (median age (IQR): 62 (40-75) years; 182 938 (52.9%) women) seeking care at least once in the hospitals in the fiscal year 2019.

Primary And Secondary Outcome Measures: We identified 33 low-value services, as defined by clinical evidence, and developed two versions of claims-based measures of low-value services with different sensitivity and specificity (broader and narrower definitions). We examined the number of low-value services, the proportion of patients receiving these services and the proportion of total healthcare spending incurred by these services in 2019. We also evaluated the 2015-2019 trends in the number of low-value services.

Results: Services identified by broader low-value care definition occurred in 7.5% of patients and accounted for 0.5% of overall annual healthcare spending. Services identified by narrower low-value care definition occurred in 4.9% of patients and constituted 0.2% of overall annual healthcare spending. Overall, there was no clear trend in the prevalence of low-value services between 2015 and 2019. When focusing on each of the 17 services accounting for more than 99% of all low-value services identified (narrower definition), 6 showed decreasing trends from 2015 to 2019, while 4 showed increasing trends. Hospital size and patients' age, sex and comorbidities were associated with the probability of receiving low-value service.

Conclusions: A substantial number of patients received low-value care in Japan. Several low-value services with high frequency, especially with increasing trends, require further investigation and policy interventions for better resource allocation.