Importance As healthcare costs continue to rise, high-income countries—including Japan—face the urgent task of reducing healthcare spending incurred by low-value care. However, evidence is limited as to which low-value care services contribute most to unnecessary healthcare spending outside of the United States.

Objective To identify which low-value care services contribute the most to unnecessary healthcare spending in Japan.

Design, Setting, and Participants The cross-sectional study of all beneficiaries using a population-based claims database from April 1, 2022, to March 31, 2023, encompassing all age groups, reflecting approximately 2% of the total Japanese population.

Main Outcomes and Measures We identified 52 low-value care services based on clinical evidence, and examined their contributions to healthcare spending using two versions of claims-based measures with different sensitivities and specificities (broader and narrower definitions). Each service was categorized into four groups based on its average per-service price: very low (<1,000 Japanese yen [JPY] = 8 US dollars [USD] in 2022), low (1,000–9,999 JPY), medium (10,000–99,999 JPY), or high (≥100,000 JPY).

Results Among 1,923,484 beneficiaries (mean [SD] age 58.6 [23.5] years; 52.7% female), we identified 3.1 million (narrower definition) to 3.7 million (broader definition) episodes of low-value care services (1.6–1.9 per capita), with 36–40% of patients receiving at least one low-value care service. These services accounted for 0.7–1.0% of total healthcare spending, amounting to 207–331 billion JPY (1.7–2.6 billion USD) when extrapolated nationwide with adjustments for age, sex, and region. When applying narrower definitions, over 99% of low-value care episodes involved very-low-cost or low-cost services, which accounted for 67% of unnecessary healthcare spending—far exceeding the 33% attributed to medium-cost or high-cost services.

Conclusion and Relevance Over one in three Japanese individuals received low-value care during 2022-2023, contributing to 0.7–1.0% of total healthcare spending. Among these services, low-cost services contributed to virtually all low-value care utilization and over two-thirds of unnecessary healthcare spending. Compared to focusing solely on high-cost services, targeting the reduction of frequently performed, lower-cost services may be a more effective strategy for reducing wasteful spending.

Question Which low-value care services—low-cost or high-cost—contribute most to unnecessary healthcare spending in Japan?

Findings In a cross-sectional study of nearly two million beneficiaries examining 52 low-value care services, over one-third received at least one such service during a one-year period, accounting for 0.7–1.0% of total healthcare spending. More than 99% of episodes were very-low- or low-cost services, accounting for over two-thirds of low-value care spending, exceeding spending from medium- and high-cost services.

Meaning Focusing on frequently performed, lower-cost services may better reduce wasteful healthcare spending than targeting only high-cost services.

Dr. Miyawaki received funding from the Ministry of Health, Labour and Welfare (23AA2004), the Japan Society for the Promotion of Science (24K02701), and the TRiSTAR program (the Strategic Professional Development Program for Young Researchers conducted by the Ministry of Education, Culture, Sports, Science and Technology) for other work not related to this study; and received consulting fees from M3, Inc. and Datack Inc.; and lecture fees from Janssen Pharma (in the last 36 months). Dr. Mafi was supported by a National Institute of Health (NIH)/National Institute on Aging (NIA) award (R01AG070017-01) and an NIH/NIA Beeson Emerging Leaders in Aging Research Career Development Award (K76AG064392-01A1) for other work not related to this study. Dr. Tsugawa received funding from NIH/NIA (R01AG068633 & R01AG082991), NIH/National Institute on Minority Health and Health Disparities (R01MD013913), and GRoW @ Annenberg for other work not related to this study; and serves on the board of directors of M3, Inc.

This study was supported by a grant from the General Incorporated Association Evidence Studio (Tokyo, Japan).

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Ethics Committee of the University of Tokyo approved this study and waived written informed consent because we retrospectively analyzed deidentified data.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

The DeSC database is a proprietary database owned by DeSC Healthcare, Inc.; therefore, it cannot be shared. Individuals who are interested in using the DeSC data should contact DeSC Healthcare, Inc.

https://desc-hc.co.jp/en