Depression has been associated with a broad range of adverse health outcomes, including impaired physical function and increased morbidity and mortality. Patients admitted for acute myocardial infarction (MI) who also were diagnosed with a major depressive disorder had a two- to four-times increased risk for cardiac mortality compared with those who had the same diagnosis and no major depressive disorder. Prior studies have concentrated on the increased risk of mortality related to depression and acute MI but have failed to study the impact of depression on community-dwelling persons. Penninx and associates studied the effect of depression on cardiac mortality in community-dwelling persons with and without cardiac disease.

The participants in the study were a random sample of community-dwelling persons in Amsterdam aged 55 to 85 years. Over a four-year period, 2,847 men and women were followed. Three data measures were used to establish the presence of coronary artery disease or congestive heart failure: patient-reported cardiac disease, a review of medications used and reports of cardiac disease by the subjects' family physicians. Cardiac mortality was established by tracing the death certificates of the participants during the study period. Effects of the presence of minor or major depression were assessed after controlling for other known cardiac risk factors.

There were 450 subjects participating in the study who had known cardiac disease, and the remaining 2,397 subjects did not have any known cardiac disease. After adjusting for confounding variables, participants with cardiac disease and minor depression had a relative risk for cardiac mortality of 1.6 (95 percent confidence interval [CI], 1.0 to 2.7) compared to those without depression. Participants with cardiac disease and major depression had a relative risk for cardiac mortality of 3.0 (95 percent CI, 1.1 to 7.8). Participants with no prior history of cardiac disease who had minor and major depression had a similar relative risk for cardiac mortality compared with participants with no depression.

The authors conclude that minor and major depression increase the risk of cardiac mortality in older patients even if they have no prior history of cardiac disease. This was particularly true for major depression, where the relative risk was more than two times that of patients with minor depression. This study needs to be followed with more clinical trials that observe the impact of treating minor and major depression on cardiac mortality outcome in persons with and without known cardiac disease.