Dimensions of socioeconomic status and clinical outcome after primary percutaneous coronary intervention

Abstract

Background: The association between low socioeconomic status (SES) and high mortality from coronary heart disease is well-known. However, the role of SES in relation to the clinical outcome after primary percutaneous coronary intervention remains poorly understood.

Methods and results: We studied 7385 patients treated with primary percutaneous coronary intervention. Participants were divided into high-SES and low-SES groups according to income, education, and employment status. The primary outcome was major adverse cardiac events (cardiac death, recurrent myocardial infarction, and target vessel revascularization) at maximum follow-up (mean, 3.7 years). Low-SES patients had more adverse baseline risk profiles than high-SES patients. The cumulative risk of major adverse cardiac events after maximum follow-up was higher among low-income patients and unemployed patients compared with their counterparts (income: hazard ratio, 1.68; 95% CI, 1.47-1.92; employment status: hazard ratio, 1.75; 95% CI, 1.46-2.10). After adjustment for patient characteristics, these differences were substantially attenuated (income: hazard ratio, 1.12; 95% CI, 0.93-1.33; employment status: hazard ratio, 1.27; 95% CI, 1.03-1.56). Further adjustment for admission findings, procedure-related data, and medical treatment during follow-up did not significantly affect the associations. With education as the SES indicator, no between-group differences were observed in the risk of the composite end point.

Conclusions: Even in a tax-financed healthcare system, low-SES patients treated with primary percutaneous coronary intervention face a worse prognosis than high-SES patients. The poor outcome seems to be largely explained by differences in baseline patient characteristics. Employment status and income (but not education level) were associated with clinical outcomes.