Impact of Individual Income Level on Late Mortality After Coronary Artery Bypass Grafting

Abstract

BackgroundCoronary artery bypass grafting (CABG) is an important and viable option for patients with symptomatic or life-threatening ischemic heart disease. Few papers have explored whether socioeconomic status is a significantly important determinant in late outcomes of CABG, and individual-level socioeconomic data were particularly scarce. This study was conducted to explore the impact of individual income level on clinical outcomes after CABG. MethodsThis nationwide longitudinal population-based study was conducted in South Korea using the National Health Insurance Service database. Overall, 29 810 adult patients who underwent first-time isolated CABG from 2005 to 2015 were included. The individual income level was stratified into 4 quartiles (Q1-Q4). The primary outcome was overall mortality. ResultsAfter adjustment for preoperative comorbidities, no significant difference in the in-hospital mortality rate was observed between the lowest (income Q1 group) and highest (income Q4 group) quartiles. The risk of overall mortality increased significantly with a reduction in income level, and having an income in the lowest quartile was a significant predictor of worse late mortality compared with the highest quartile (hazard ratio, 1.23; 95% CI, 1.17-1.30). Moreover, the overall incidence of stroke and myocardial infarction was significantly higher in the income Q1 group than in the income Q4 group. The median follow-up duration was 7.0 years (interquartile range, 4.1-10.2 years). ConclusionsPatients with a lower individual income level had an increased risk of the poorer long-term outcomes after CABG compared with the highest individual income level quartile.