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Etiology

Living alone after myocardial infarction was an independent risk factor for recurrent events

ACP J Club. 1992 May-June;116:88. doi:10.7326/ACPJC-1992-116-3-088


Source Citation

Case RB, Moss AJ, Case N, McDermott M, Eberly S. Living alone after myocardial infarction. Impact on prognosis. JAMA. 1992 Jan 22/29;267:515-9.


Abstract

Objective

To determine if a disrupted marriage or living alone at the time of a myocardial infarction is an independent risk factor for a subsequent major cardiac event.

Design

A cohort (the placebo group in a randomized trial) was followed for ≥ 1 year.

Setting

Community and university hospitals in North America.

Patients

1234 patients between 25 and 75 years of age with enzyme-documented acute (transmural or non-Q-wave) myocardial infarction were enrolled 3 to 15 days after an infarction. Patients with other serious diseases were excluded. Patients were followed for a minimum of 12 months and a maximum of 50 months (mean 25 months).

Assessment of risk factors

Psychosocial data were collected at enrollment. Patients indicated their marital status and the number of people with whom they lived. Changes in these variables were not recorded during follow-up. 6 other physiologic and nonphysiologic factors (out of 9 originally considered) that provided the best prediction of outcome were included in the analysis.

Main outcome measures

Major cardiac event (recurrent nonfatal infarction or cardiac death) as determined by a committee blinded to patients' psychosocial status.

Main results

226 major cardiac events occurred in 1234 patients (18.3%). Living alone was an independent risk factor for a subsequent major cardiac event, with a hazard ratio of 1.54 (95% CI 1.04 to 2.29). Most of the cardiac events in those living alone occurred within the first 6 months of follow-up. At 6 months, the cumulative rate of recurrent cardiac events for those living alone was 15.8% compared with 8.8% for those living with other persons. The cumulative rate of recurrent cardiac events was higher for those living alone throughout the follow-up period (P = 0.001). A disrupted marriage was not an independent risk factor (hazard ratio 1.1, P > 0.2), although those living with another person after disruption had a reduced event rate (17.4% vs 27.3%, P < 0.05).

Conclusion

Living alone at the time of initial myocardial infarction was an independent risk factor for subsequent nonfatal myocardial infarction or cardiac death.

Sources of funding: In part, Goedecke Aktiengeselleschaft; Laboratorios Dr Esteve, SA; Marion Laboratories, Inc.; Nordic Laboratories, Inc.; Lars Synthelabo; Tanabe Seiyaku Co. Ltd.; Warner-Lambert International.

Address for article reprint: Dr. R.B. Case, Department of Medicine, St. Luke's-Roosevelt Hospital, Amsterdam Avenue at 114th Street, New York, NY 10025, USA.


Commentary

This study by Case and colleagues is of considerable clinical interest and provides meaningful information about the effect of the psychosocial environment on the prognosis of survivors of acute myocardial infarction. The data show that the cardiac event rate was higher in patients with New York Heart Association class II to IV, with ventricular premature complexes ≥ 10/h, and with previous myocardial infarction. Patients living alone were slightly older, and more of them had these other risk factors. None of these differences, however, accounted for the increased risk associated with living alone.

One limitation of this study is that the study population consisted largely of white men (roughly 90% white and 80% men). The results may not apply to all patients with acute myocardial infarction. The results, however, confirm earlier observations (1) about the effect of psychosocial status on coronary artery disease and related event rates. Ruberman and colleagues (1) found that a low level of education was an independent predictor of cardiac mortality in 1739 men surviving acute myocardial infarction. Patients who did not complete high school (< 12 years of formal education) were also at higher risk in the study by Case and colleagues. However, the difference in education of those living alone compared with that of others was small (40% vs 36% with < 12 years) and did not account for the poorer prognosis associated with living alone.

Why people living alone are at increased risk is not clear. Greater psychosocial stress may be one cause. Certainly, more work is needed in this area, and the results of these studies point to the need for evaluation of psychosocial conditions when dealing with patients who have had an acute myocardial infarction.

Prakash C. Deedwania, MD
University of CaliforniaSan Francisco, California, USA

Prakash C. Deedwania, MD
University of California
San Francisco, California, USA


Reference

1. Ruberman W, Weinblatt E, Goldberg JD, Chaudhary BS. Psychological influences on mortality after myocardial infarction. N Engl J Med. 1984;311:552-9.