Depression may give heart disease patients even greater risk of heart failure, according to a new study by Utah doctors.

Cardiac researchers at Intermountain Medical Center are the first to investigate the link, finding that a subsequent diagnosis of depression increases the likelihood of developing heart failure and that antidepressant medications don't necessarily mitigate the risk.

"Our findings indicate that it may be important for clinicians to keep in mind that although a patient's depressive symptoms may improve, the risk for harmful cardiovascular outcomes relates to depression might not," said Dr. Heidi May, an epidemiologist at IMC and lead author of the study. She said data suggest that depression is an important and emerging risk factor for heart failure among patients with coronary heart disease.

The study followed more than 13,700 patients diagnosed with heart disease at IMC. One in 10 patients was later diagnosed with depression. Participants were drawn from the cardiac catheterization registry of the Intermountain Heart Collaborative Registry at the center, which is one of the leading heart hospitals in the country.

Researchers found that a depression diagnosis following coronary heart disease was associated with a two-fold increased risk for the incidence of heart failure. The risk remained, but was slightly lower after adjusting for other cardiovascular factors, including diabetes, hypertension and age. The incidence of heart failure among patients who were not depressed after being diagnosed with coronary artery disease was 3.6 per 100 compared with 16.4 per 100 for those with a post-heart disease depression diagnosis, according to the study.

The increase in the risk of a heart failure diagnosis was evident at the start of follow-up for those with a diagnosis of depression post-coronary heart disease, May said.

"Patients need to be carefully screened for depression so that interventions that alter some of the risk associated with depression can be used and the related risk of heart failure and other cardiovascular events can be diminished," she said.

The entire study will be published in the April 21 issue of the Journal of American College of Cardiology. Researchers believe it represents an important area of inquiry given the widespread burden of heart failure and depression, both of which can severely limit daily functioning and contribute to high rates of health-care utilizations.

Previous studies have shown that depression in patients with heart failure increases the risk of hospitalization and death. Depression among heart disease patients, May said, has also been found to be predictive of future cardiovascular events, such as heart attack and even death.

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The study identified other risk factors associated with depression and heart failure, including smoking, hypertension, diabetes and being overweight. Prior studies have reported that patients with depression are less likely to practice good health habits or follow doctors' orders in taking medications and keeping appointments.

Although the study identifies a relationship between depression and heart failure in heart disease patients, May believes additional studies would help to further explore the association, as well as other cardiovascular outcomes.