ObjectiveThe objective of this study was to compare the utilization of, and outcome from, critical care services in selected medical centers providing secondary and tertiary care in the United States and Japan.DesignProspective data collection on 1,292 patients from each of the participating Japanese study hospitals in 1987 to 1989 and compared with the 5,030 patients in the United States 1982 Acute Physiology and Chronic Health Evaluation (APACHE II) database used to develop the APACHE II equation. Detailed organizational characteristics of the participating ICUs and hospitals were also obtained.SettingData collection took place in the ICUs of 13 U.S. hospitals and six Japanese hospitals.PatientsData were collected on consecutive, unselected patients from medical, surgical, and mixed medical/surgical critical care units, with a spectrum of medical and surgical diagnoses.Measurements and Main ResultsU.S. and Japanese ICUs have a similar array of diagnostic and therapeutic modalities. Only 2% (range 0.6 to 3.5) of beds in Japanese hospitals were designated to intensive care. The organization of the Japanese and U.S. ICUs varied by hospital. There were significantly fewer women admitted to Japanese ICUs and a substantially lower proportion of low-risk-of-death patients. Despite a rapidly aging population, there were relatively fewer elderly patients with chronic health ailments in the Japanese ICU population (8%) compared with the U.S. cohort (18%).ConclusionsIn this sample of hospitals, similar high-technology critical care is available in the United States and Japan. Variations in utilization between the two countries represent differences in case mix and bed availability. The APACHE II equation stratified patients in the Japanese patient cohort across the full spectrum of increasing severity of illness.