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Etiology

Low social and economic factors plus lack of a spouse or confidant increased mortality in patients with coronary artery disease

ACP J Club. 1992 May-June;116:89. doi:10.7326/ACPJC-1992-116-3-089

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Source Citation

Williams RB, Barefoot JC, Califf RM, et al. Prognostic importance of social and economic resources among medically treated patients with angiographically documented coronary artery disease. JAMA. 1992 Jan 22/29;267:520-4.


Abstract

Objective

To ascertain whether diminished social and economic resources increase the risk for cardiovascular mortality in medically treated patients with coronary artery disease.

Design

Cohort analytic study with a median follow-up of 9 years.

Setting

University medical center in the United States.

Patients

1368 symptomatic patients (99% white, median age 52 y, 82% men) with ≥ 75% stenosis of at least 1 major coronary artery. Patients were eligible if they were admitted for their first cardiac catheterization, did not have unstable anginal symptoms, and could read at ≥ sixth-grade level. Selection for catheterization effectively excluded patients with major comorbidity. 597 eligible patients were not enrolled because of logistic problems, patient refusal, or missing data for key medical variables. 7 patients were lost to follow-up.

Assessment of risk factors

A battery of questions concerning psychosocial, economic, and functional status was administered at study enrollment.

Main outcome measure

Survival time until cardiovascular death. Deaths were classified by a committee blinded to socioeconomic assessments. Causes of death were categorized as cardiovascular and noncardiovascular, based on information provided by the patients' physicians. Patient follow-up was conducted at 6 and 12 months after catheterization and annually thereafter. Cox model survival analyses were used to assess the relation of the socioeconomic variables to cardiovascular mortality.

Main results

Independent of disease severity, patients with annual household incomes of ≥ U.S. $40 000 had a mean 5-year survival rate of 91% compared with 76% in patients with incomes < $10 000 (Cox model adjusted hazard ratio 1.9, 95% CI 1.57 to 2.32). Unmarried patients without a confidant (n = 35) had a 5-year survival rate of 50% compared with 82% in patients with either a spouse or confidant (hazard ratio 3.34, CI 1.84 to 6.20). The only other statistically significant economic or social factor was the number of persons dependent on the household incomes.

Conclusion

Independent of all major clinical and angiographic prognostic factors, a low level of economic and social resources and lack of a spouse or confidant identified a high-risk group for cardiovascular mortality in medically treated patients with coronary artery disease.

Sources of funding: Agency for Health Care Policy and Research; National Heart, Lung, and Blood Institute; National Institute of Mental Health; Robert Wood Johnson Foundation.

Address for article reprint: Dr. R.B. Williams, P.O. Box 3926, Duke University Medical Center, Durham,NC 27710, USA.


Commentary

This paper confirms the large body of data accumulated over the past 2 decades, linking social support to mental and physical health in general and to coronary heart disease in particular. Hinkle and colleagues, probably for the first time, documented that lower socioeconomic status is associated with increased incidence of coronary events (1). Rose and Marmot reached a similar conclusion, ascertaining that there was an inverse relation between social class and coronary heart disease (2). Data from Statistics Canada have shown that mortality is 2.5 times higher in the low income groups when compared with the highest income groups in Canada. Although little new knowledge is generated in Williams and colleagues' paper, it is the first time that cardiac catheterization data have been included to control for the severity of coronary artery disease.

For clinical practice, it is important to realize that a patient in a low socioeconomic class is a higher risk patient. The question is how much the awareness of this fact helps. Few proper randomized, controlled trials have tested the efficacy of intervention strategies to rectify risk factors connected with socioeconomic status or lack of a supportive network. The authors quote 1 paper reporting an attempted intervention along these lines.

If this paper has a bottom line, it is the need to develop well-designed studies to test the effect on morbidity and mortality of interventional strategies that change behavioral traits and develop methods for providing a social-support network for the most needy patients.

J. George Fodor, MD, PhD
Memorial University of NewfoundlandSt. John's, Newfoundland, Canada


References

1. Hinkle LE, Whitney LH, Lehman EW. Occupation, education and coronary heart disease. Science. 1968;161:238-46.

2. Rose GA, Marmot MG. Social class and coronary heart disease. Br Heart J. 1981; 45:13-9.