Depression predicting death after myocardial infarction
ACP J Club. 1994 Mar-April;120:45. doi:10.7326/ACPJC-1994-120-2-045
Frasure-Smith N, Lespérance F, Talajic M. Depression following myocardial infarction. JAMA. 1993 Oct 20;270:1819-25.
To determine if the diagnosis of major depression has an independent effect on mortality in patients who have had a myocardial infarction (MI).
6-month cohort study with adjusted control groups.
A university-affiliated cardiac hospital in Quebec.
Patients hospitalized for acute MI between July 1991 and June 1992 were asked to participate. Patients spoke English or French sufficiently well and were stable enough to be interviewed between 5 and 15 days after the MI. Exclusion criteria were any other medical condition likely to influence 6-month survival or major cognitive problems. Of 332 eligible patients, 222 (mean age, 60 y; 49 women) agreed to participate and survived to hospital discharge.
Assessment of Risk Factors
Patients were interviewed in hospital within 2 weeks after MI with regard to education, living arrangements, existence of close friends, and smoking status. They were asked questions based on the National Institute of Mental Health Diagnostic Interview Schedule (DIS) for indication of major depression. Researchers and clinicians were blinded to the patients' DIS classifications. Baseline clinical information was gathered from patients' charts and included previous MI; left ventricular ejection fraction; Killip class; frequency of premature ventricular contractions; thrombolytic treatment; and prescription of β-blockade agents, aspirin, and warfarin at discharge.
Main Outcome Measures
Survival status 6 months after MI.
At baseline interview, 35 patients (16%) were diagnosed with major depression. 6 months after MI, 12 patients had died; 6 were depressed and 6 were not depressed. Patients who were depressed had higher mortality than patients who were not depressed (hazard ratio, 5.74, 95% CI, 1.86 to 17.8). The association remained after controlling for 2 multivariate predictors, previous MI and Killip class (hazard ratio, 4.29; CI, 1.36 to 13.6). Other independent multivariate baseline predictors of mortality were Killip class > 1 for the whole sample and previous MI for those patients who had Holter monitoring (n = 197) (P < 0.05).
Major depression shortly after a myocardial infarction was a risk factor for mortality in patients during the next 6 months.
Sources of funding: Quebec Health Research Fund; Quebec Council of Social Research; Medical Research Council of Canada; Montreal Heart Institute; Heart and Stroke Foundation of Canada.
For article reprint: Dr. N. Frasure-Smith, Research Center, Montreal Heart Institute, 5000 Belanger East, Montreal, Quebec, H1T 1C8. FAX 514-376-1355.
Depression is a common treatable condition that is underdiagnosed in medical patients (1, 2). The study by Frasure-Smith and colleagues is important because it is one of a small number of cohort studies of depression in patients with acute MI.
Patients were entered into the study in a uniform manner using well-accepted criteria for acute MI and depression. Depression was diagnosed in 16% of patients. After controlling for other variables affecting mortality, patients who were depressed were approximately 4 times more likely to die by 6 months than patients who were not depressed. The study patients, however, may have differed from the general population of patients with acute MI. Study patients were admitted to a cardiac (vs. general) hospital. Second, approximately one third of patients eligible for the study refused to participate. Finally, study participants were younger (mean age, 60 vs. 63 years) and were more likely to be men (72% of men and 57% of women participated) than were nonparticipants.
Although patients in this study were a selected group, the results are impressive. Depression appears to be common and appears to be an important prognostic marker for death after an acute MI. What remains unknown is whether treatment for depression will change the risk for death of these patients. Despite this, physicians should be diligent in looking for signs and symptoms of depression after an acute MI.
Martha Gerrity, MD, PhD
Oregon Health Sciences University Portland, Oregon, USA