Institutional Variance in Mortality after Percutaneous Coronary Intervention for Acute Myocardial Infarction in Korea, Japan, and Taiwan

Document Type : Original Article


1 Data Science Center, Jichi Medical University, Shimotsuke, Japan

2 Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan

3 Institute of Health and Environment, Seoul National University, Seoul, South Korea

4 Department of Healthcare Administration, College of Medicine, I-Shou University, Kaohsiung, Taiwan

5 Division of Social Welfare and Health Administration, Wonkwang University, Iksan, South Korea

6 Department of Health Policy and Informatics, Tokyo Medical and Dental University Graduate School, Tokyo, Japan

7 Institute of Health Policy and Management, College of Public Health, National Taiwan University, Taipei, Taiwan

8 Department of Public Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, South Korea

9 Institute of Aging, Seoul National University, Seoul, South Korea

10 SOCIUM - Research Center on Inequality and Social Policy, University of Bremen, Bremen, Germany


Although there have been studies that compared outcomes of patients with acute myocardial infarction (AMI) across countries, little focus has been placed on institutional variance of outcomes. The aim of the present study was to compare institutional variance in mortality following percutaneous coronary intervention (PCI) for AMI and factors explaining this variance across different health systems.

Data on inpatients who underwent PCI for AMI in 2016 were obtained from the National Health Insurance Data Sharing Service in Korea, the Diagnosis Procedure Combination (DPC) Study Group Database in Japan, and the National Health Insurance Research Database (NHIRD) in Taiwan. Multilevel analyses with inpatient mortality as the outcome and the hierarchical structure of patients nested within hospitals were conducted, adjusting for common patient-level and hospital-level variables. We compared the intraclass correlation coefficient (ICC) and the proportion of variance explained by hospital-level characteristics across the three health systems.

There were 17 351 patients from 160 Korean hospitals, 29 804 patients from 660 Japanese hospitals, and 10 863 patients from 104 Taiwanese hospitals included in the analysis. Inpatient mortality rates were 6.3%, 7.3%, and 6.0% in Korea, Japan, and Taiwan, respectively. After adjusting for patient and hospital characteristics, Taiwan had the lowest variation in mortality (ICC, 1.8%), followed by Korea (2.2%) and then Japan (4.5%). The measured hospital characteristics explained 38%, 19%, and 9% of the institutional variance in Korea, Taiwan, and Japan, respectively.

Korea, Japan, and Taiwan had similarly uniform outcomes across hospitals for patients undergoing PCI for AMI. However, Japan had a relatively large institutional variance in mortality and a lower proportion of variation explainable by hospital characteristics, compared with Korea and Taiwan.


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  • Receive Date: 19 September 2021
  • Revise Date: 14 August 2022
  • Accept Date: 26 February 2023
  • First Publish Date: 28 February 2023