Patients with coronary artery disease may be at increased risk of death while using antidepressant drugs, according to the results of an observational study reported at the American Psychosomatic Society in Denver.

However, “people with heart disease should definitely not stop taking their antidepressants, because we do not know if antidepressants were causing this (increased risk) or if it was due to some other characteristics of folks who are on antidepressants,” said presenter Dr. Lana L. Watkins.

Their study evaluated “the contribution of anxiety and depression to the risk of sudden cardiac death in patients with coronary artery disease,” the researcher noted.

Watkins and her colleagues at Duke University in Durham, North Carolina, monitored depressive symptoms and antidepressant use among 921 patients ages 29 to 90 years who were hospitalized for coronary angiography, a procedure used to diagnose heart disease. “All of the patients had a history of or current coronary artery disease,” she said.

Antidepressants were being used by 19.4 percent of subjects. Two thirds of the antidepressants were selective serotonin reuptake inhibitors, a relatively new class of antidepressants that include drugs such as Prozac.

During an average of three years of follow-up, 21.4 percent of the patients taking antidepressants died, compared with 12.5 percent of those not on antidepressants. After adjusting for demographic factors, cardiac risk factors, scores on the Beck Depression Inventory test, and the presence of other illness, antidepressant use was an independent risk factor for mortality, increasing the risk by 62 percent.

“It’s possible that patients taking antidepressants had other factors” (that could account for the increased risk), so the finding could just be incidental, Watkins emphasized.

For example, people on antidepressants may be sicker or more depressed, she explained, which in turn could lead to suppression of the immune system or an increase in cardiovascular risk factors such as high blood pressure, physical inactivity or alcohol or tobacco abuse.

“That is why it would be very premature for patients to stop taking their medications.”

She does however advise physicians to closely monitor their patients with coronary artery disease who are taking antidepressants. Meanwhile, she and her associates are planning a more rigorous trial to more closely examine the factors contributing to mortality risk in patients with coronary heart disease.