Regional differences in treatment frequency and case-fatality rates in korean patients with acute myocardial infarction using the Korea national health insurance claims database: findings of a large retrospective cohort study.

Issues regarding healthcare disparity continue to increase in connection with access to quality care for acute myocardial infarction (AMI), even though the case-fatality rate (CFR) continues to decrease. We explored regional variation in AMI CFRs and examined whether the variation was due to disparities in access to quality medical services for AMI patients. A dataset was constructed from the Korea National Health Insurance Claims Database to conduct a retrospective cohort study of 95,616 patients who were admitted to a hospital in Korea from 2003 to 2007 with AMI. Each patient was followed in the claims database for information about treatment after admission or death. The procedure rate decreased as the region went "down" from Seoul to the county level, whereas the AMI CFR increased as the county level as a function of proximity to the county level (30-day AMI CFRs: Seoul, 16.4%; metropolitan areas, 16.2%, cities; 18.8%, counties, 39.4%). Even after adjusting for covariates, an identical regional variation in the odds of patients receiving treatment services and dying was identified. After adjusting for invasive and medical management variables in addition to earlier covariates, the death risk in the counties remained statistically significantly higher than in Seoul; however, the degree of the difference decreased greatly and the significant differences in metropolitan areas and cities disappeared. Policy interventions are needed to increase access to quality AMI care in county-level local areas because regional differences in the AMI CFR are likely caused by differences in the performance of medical and invasive management among the regions of Korea. Additionally, a public education program to increase the awareness of early symptoms and the necessity of visiting the hospital early should be established as the first priority to improve the outcome of AMI patents, especially in county-level local areas.