by Michelle Rizzo

Last Updated: 2007-09-28 19:45:50 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Patients who become depressed after a major coronary event have a significantly higher mortality rate than those who are not depressed, researchers note, but cardiac rehabilitation and exercise training can substantially reduce depression and the excess mortality.

Depression and depressive symptoms develop in up to 20% of patients with coronary heart disease, note Dr. Richard V. Milani and Carl J. Lavie at the Ochsner Medical Center in New Orleans. "Although their presence identifies patients at high risk for adverse cardiovascular outcomes, including myocardial infarction and death, it remains underappreciated as a coronary risk factor."

The researchers retrospectively examined the impact of cardiac rehabilitation on depression and subsequent long-term mortality in 522 consecutive patients with coronary artery disease. The patients, mean age 64 years, completed cardiac rehabilitation between January 2000 and July 2005. The investigators compared these patients with a control group of 179 coronary artery disease patients who did not complete rehabilitation.

Questionnaires were used to assess depressive symptoms at baseline and after rehabilitation. Mortality was evaluated after a mean follow-up of 1296 days. The findings are published in the September issue of the American Journal of Medicine.

Of the 522 patients in the treatment group, 91 (17%) had depressive symptoms at baseline. The prevalence of depression decreased 63%, from 17% to 6%, following rehabilitation (p < 0.0001).

In the control group, depressed patients were at 3 times the risk of dying than those without depressive symptoms.

Among subjects who completed rehabilitation, continued depression increased mortality four-fold higher compared with their counterparts (22% versus 5%, respectively; p = 0.0004).

However, depressed patients who completed cardiac rehabilitation and whose depression had resolved had a nearly 4-fold decrease in mortality compared with depressed patients who did not complete the rehabilitation program (30% versus 8%, respectively; p = 0.0005).

Reductions in depressive symptoms and associated mortality were linked to improvements in fitness, according to the authors. However, similar improvements in depression were observed in patients with modest and substantial increases in exercise capacity.

"Depression is a prevalent risk factor and is modifiable," Dr. Milani said in an interview with Reuters Health. "As such, efforts should be made to screen patients for this and utilize effective measures to treat those with depression."

"We believe that many of the health benefits attributed to exercise are in fact related to improving high-risk behaviors," Dr. Milani said. "As such, we are evaluating how much of a role behavior modification has in exercise-related health benefits."

Am J Med 2007;120:799-806.