Researchers at the University of Kentucky, in Lexington, found negative thinking accounts for more than a third of depressive symptoms in patients with heart failure, independent of sociodemographic factors, antidepressant therapy, and severity of heart failure.

"Depression is underdiagnosed and undertreated in patients with heart failure," lead study author Rebecca Dekker said. "Given the life-or-death consequences of depression in these patients, we need to do a better job of not only recognizing depression but treating it."

The study was presented here at the American Heart Association 2008 Scientific Sessions.

According to Dekker, treatments that target negative thinking may help reduce depressive symptoms in this patient group, but further research is needed to determine how such interventions would affect outcomes.

In the meantime, "clinicians need to recognize that patients with heart failure who express negative thoughts such as 'I'm a burden to my family' or 'I'm a failure' are at higher risk for depressive symptoms and need to be screened and, if necessary, treated for depression," she said.

Clinical depression is a significant problem in heart-failure patients, affecting approximately 20% of this patient group, and is an independent predictor of morbidity and mortality.

To determine the preponderance of negative thinking and whether this thought pattern independently predicts depressive symptoms in patients with heart failure, the researchers performed a cross-sectional study. They recruited 154 heart-failure patients, with a mean age of 61 years, from a single outpatient heart-failure center

Negative thinking was measured using the Crandell Cognitions Inventory, a 45-item questionnaire that measures negative thoughts about the self, the world, the future, and relationships.

Depressive symptoms were measured using the Beck Depression Inventory (BDI).

The mean level of negative thinking was 60±26, which is higher than the reported mean of 45±8 for nondepressed, healthy controls.

One-third of the study subjects had clinically significant depressive symptoms (BDI>13). Patients with depressive symptoms had substantially higher levels of negative thinking than other patients.

Negative thinking alone explained 38% of the variance in depressive symptoms, after researchers controlled for age, sex, marital status, left ventricular ejection fraction, and ACE-inhibitor use.

As a result of the findings, the investigators plan to conduct a randomized controlled trial to test an intervention designed to reduce negative thinking in patients hospitalized with heart failure.

"This will be the first study to test the effects of a 'brief' bedside cognitive therapy session on negative thinking, depressive symptoms, and cardiac event-free survival in hospitalized heart-failure patients," said Dekker.