Disparities in Mortality and Cardiovascular Events by Income and Blood Pressure Levels Among Patients With Hypertension in South Korea

Abstract

Background Socioeconomic status is associated with differences in risk factors of cardiovascular disease and increased risks of cardiovascular disease and mortality. However, it is unclear whether an association exists between cardiovascular disease and income, a common measure of socioeconomic status, among patients with hypertension. Methods and Results This population-based longitudinal study comprised 479 359 patients aged ≥19 years diagnosed with essential hypertension. Participants were categorized by income and blood pressure levels. Primary end point was all-cause and cardiovascular mortality and secondary end points were cardiovascular events, a composite of cardiovascular death, myocardial infarction, and stroke. Low income was significantly associated with high all-cause (hazard ratio [HR], 1.26; 95% CI, 1.23-1.29, lowest versus highest income) and cardiovascular mortality (HR, 1.31; 95% CI, 1.25-1.38) as well as cardiovascular events (HR, 1.07; 95% CI, 1.05-1.10) in patients with hypertension after adjusting for age, sex, systolic blood pressure, body mass index, smoking status, alcohol consumption, physical activity, fasting glucose, total cholesterol, and the use of aspirin or statins. In each blood pressure category, low-income levels were associated with high all-cause and cardiovascular mortality and cardiovascular events. The excess risks of all-cause and cardiovascular mortality and cardiovascular events associated with uncontrolled blood pressure were more prominent in the lowest income group. Conclusions Low income and uncontrolled blood pressure are associated with increased all-cause and cardiovascular mortality and cardiovascular events in patients with hypertension. These findings suggest that income is an important aspect of social determinants of health that has an impact on cardiovascular outcomes in the care of hypertension.