Patients with heart disease who are subsequently diagnosed with depression are at greater risk for heart failure (HF), a condition in which the heart can't pump enough blood throughout the body, according to a new study published in the April 21, 2009, issue of the Journal of the American College of Cardiology.
This study—the first to investigate the influence of depression after heart disease on the likelihood of developing HF—also found that taking antidepressant medications to ease depressive symptoms did not appear to mitigate this risk.
"Our data suggest that depression is an important and emerging risk factor for heart failure among patients with coronary heart disease," said Heidi May, Ph.D., M.S.P.H., epidemiologist, Intermountain Medical Center, Murray, Utah. "Interestingly, when we stratified patients with depression by whether they received antidepressant medication or not, the incidence of heart failure didn't change. This finding may indicate that antidepressants may not be able to alter the physical or behavioral risks associated with depression and heart failure, despite a potential improvement in depressive symptoms."
Patients (n = 13,708) without a diagnosis of HF and depression and who were not prescribed antidepressant medication at the time of CAD diagnosis were studied. Of these, one out of 10 (n=1,377) was later diagnosed with depression.
Data reveal that a depression diagnosis following CAD was associated with a 2-fold increased risk for the incidence of HF (p < 0.0001). This risk remained, but was slightly lower (HR: 1.50, 95% CI: 1.38 to 1.63, p < 0.0001) after adjusting for other cardiovascular risk factors (e.g., diabetes, hypertension, age). The incidence of HF among patients who were not depressed after being diagnosed with coronary artery disease (CAD) was 3.6 per 100 compared with 16.4 per 100 for those with a post-CAD depression diagnosis. The increase in the risk of a HF diagnosis was evident at the start of follow-up for those with a diagnosis of depression post-CAD.
This prospective study represents an important area of inquiry given the widespread burden of HF and depression, both of which can severely limit daily functioning and contribute to high rates of healthcare utilizations. Furthermore, previous studies have shown that depression in patients with HF increases the risk of hospitalization and death. Depression among heart disease patients has also been found to be predictive of future cardiovascular events, such as heart attack and even death.
For those with available medication records (n = 7,719), patients subsequently diagnosed with depression were stratified by use of antidepressant medications. No difference was found between depressed patients using or not using antidepressants (HR: 0.84, p = 0.24).
"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 related to depression might not," said May. "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."
There are a number of other risk factors associated with depression and HF, including smoking, hypertension, diabetes and being overweight. Prior studies have reported that patients with depression are also less likely to practice good health habits or adhere to treatment regimens (e.g., taking medications properly, following a recommended exercise program and keeping scheduled appointments).
Study participants were drawn from the cardiac catheterization registry of the Intermountain Heart Collaborative Study and used physician-diagnosed or ICD-9 codes to identify HF and depression diagnoses. Patients were followed until HF diagnosis or death. Average follow up was 5.6±3.6 years.
May added that future studies are needed to further explore the association of depression and heart failure, as well as other cardiovascular outcomes. She reports no conflict of interest.