National cost of intensive care in Japan from 2018 to 2022

Intensive care is a cornerstone of modern health systems, yet it remains among the most resource-intensive and costly forms of care. While intensive care unit (ICU) costs represent a substantial portion of health care expenditures in many high-income countries, national-level data on ICU costs in Japan have been lacking. We aimed to estimate national ICU costs in Japan using administrative and hospital-level data, employing internationally comparable methods.

We conducted a nationwide retrospective cohort study using the Diagnosis Procedure Combination Study Group database and the Hospital Bed Function Report during fiscal years 2018-2022. ICU costs were estimated using a bottom-up costing approach aligned with the method used in major international studies, and focused on certified adult and pediatric ICUs. Macroeconomic impact, temporal trends, and regional variation were assessed. We also analyzed the cost of intermediate care units (IMCU) and IMCU-ICU ratio.

A total of 1,453,929 ICU patients were identified in the DPC Study Group database from 2018 to 2022, which covers 68.2% of all ICU beds in Japan. The mean ICU cost per patient-day was ¥197,277 (approximately $1,793 USD), and the estimated national ICU cost over the 2018-2022 period was ¥1,785 billion (mean ¥357 billion per year). This represented 0.065% of nominal gross domestic product (GDP), 0.56% of total health expenditures, 1.42% of hospital expenditures, and 2.17% of inpatient expenditures. The macroeconomic impact of ICU care was stable from 2018 to 2022. The proportion of ICU costs relative to nominal GDP, total health expenditures, and hospital expenditures in Japan was substantially lower than in the United States, Canada, and Australia. Regional variation was pronounced, with up to a 7.5-fold difference across prefectures. The estimated national IMCU cost over the 2018-2022 period was ¥2,838 billion (mean ¥568 billion per year), approximately 1.5 times greater than ICU cost (IMCU-ICU ratio is approximately 1.59).

This study provides the first comprehensive national estimates of ICU costs in Japan using internationally aligned methods. These findings indicate lower ICU spending in Japan than in other high-income countries.