Less affluent area of residence and lesser-insured status predict an increased risk of death or myocardial infarction after angiographic diagnosis of coronary disease☆

Abstract 

Purpose

Low socioeconomic status (SES) predicts coronary artery disease (CAD) onset, but its value among patients with CAD is uncertain. Geographic measures (e.g., residential neighborhood) may predict risk, but this requires further evaluation.

Methods

A cohort of 3410 patients with significant, angiographically-defined CAD (≥1 lesion of ≥70% stenosis) joined a registry during the period between 1993 and 2000 and was followed for 6.7 years (median 3.7 years). A geographic SES measure—residential economic status (RES)—and insurance type were examined for association with mortality or myocardial infarction (MI).

Results

In Cox regression adjusting for 17 covariates, lower RES quartile was associated with increased death/MI (p-trend<0.001), death (p-trend=0.001), and MI (p-trend=0.07). First RES quartile (vs. fourth) predicted death/MI (hazard ratio [HR]=1.32, 95% confidence interval [CI]=1.07–1.62, p=0.01) and death (HR=1.46, CI=1.12–1.91, p=0.006), but not MI (HR=1.18, p=0.31). Compared with private insurance, self-pay (HR=1.88, p=0.053), charity care (HR=1.71, p<0.001), and Medicaid (HR=1.43, p=0.24), but not Medicare (HR=0.95, p=0.68), were associated with death/MI.

Conclusions

Both geographic (RES) and economic (insurance) measures of SES independently predicted risk of death/MI in a large population with angiographically-defined CAD. This suggests that SES remains a significant predictor of health outcomes after CAD has developed, and that geographic measures of SES deserve further evaluation.

Keywords:  Socioeconomic Factors, Coronary Disease, Death, Myocardial Infarction, Geography, Insurance, Medicare, Medicaid, Medically Uninsured

Abbreviations:  ACE, angiotensin-converting enzyme, CABG, coronary artery bypass graft, CAD, coronary artery disease, CHF, congestive heart failure, CI, 95% confidence interval, HR, hazard ratio, IHC, Intermountain Health Care, MI, myocardial infarction, PCI, percutaneous coronary intervention, SES, socioeconomic status, RES, residential economic status