Disparities in All-Cause and Cause-specific mortality by Health Insurance Status in Korea

Abstract

Abstract Background Although socioeconomic status affects health outcomes, limited research has explored how South Korea’s National Health Insurance system affects mortality rates. This study aimed to investigate whether insurance type and economic status according to premiums are associated with mortality. Methods Based on the National Health Insurance Service-Health Screening cohort, 246,172 men and 206,534 women aged 40 or older at baseline were included. Insurance status was categorized as employee-insured (EI) or self-employed-insured (SI), and economic status was categorized as low, medium, or high according to insurance premiums. Mortality was determined by linking death records. Cox proportional hazards models was used to analyze the association between insurance factors, all-cause and cause-specific mortality. Results After adjusting for various factors, SI group was at a higher risk of all-cause mortality compared to EI groups (adjusted hazard ratio (HR) [95% CI] 1.13 [1.10—1.15] for men and 1.18 [1.15—1.22] for women). Individuals in the lower economic status had higher risk of all-cause mortality in both sexes, compared to high economic status (adjusted HR [95% CI] of men mid and low EI, 1.25 [1.21—1.29] and 1.37 [1.33—1.42], respectively; women mid and low EI, 1.06 [1.01—1.11] and 1.07 [1.02—1.13], respectively; men mid and low SI, 1.33 [1.28—1.38] and 1.56 [1.59—1.63], respectively; women mid and low SI, 1.18 [1.12—1.31] and 1.25 [1.19—1.31], respectively). Similar trends were observed after stratification according to cause-specific mortality rates. Conclusion SI and lower economic status were associated with an increased risk of mortality. Trial Registration This study was approved by the Institutional Review Board of Chungbuk National University Hospital (CBNUH-202211-HR-0236) and adhered to the principles of the Declaration of Helsinki (1975).