Controlling depression in patients with heart failure can improve health status, social functioning and quality of life, according to a new study by psychiatrists and cardiologists at the UC Davis and Duke University schools of medicine.
While depression is known to worsen a variety of diseases, the current study is one of the first to show that reducing symptoms of the mental health condition can benefit physical health. The study is available online now and will be distributed in the print issue of Circulation: Heart Failure on Nov. 20.
"The improved endurance measurements were especially striking," said study lead author Glen Xiong, associate clinical professor of psychiatry and behavioral sciences at UC Davis. "I think clinicians will be more motivated to both screen and treat depressive symptoms in people with heart failure because of the significant functional improvements."
Heart failure causes the heart's pumping action to become progressively weak and, even with advanced treatments, is associated with increased disability and mortality. The estimated direct and indirect costs of the disease in the U.S. are more than $37 billion. It affects more than 5 million Americans, about 20 percent of whom are also diagnosed with depression.
For the study, Xiong and his colleagues conducted a secondary analysis on data obtained from the 2008 Sertraline Against Depression and Heart Disease in Chronic Heart Failure (SADHART-CHF) study. This multi-center clinical trial evaluated the efficacy of the antidepressant medication sertraline in reducing depressive and cardiac symptoms among 469 men and women 45 years of age or older with both heart failure and major depressive disorder.
Sertraline is from a class of medications called selective serotonin reuptake inhibitors that can help balance brain chemicals linked with panic disorder and depression. The initial SADHART-CHF results found that sertraline treatment, however, did not significantly differ from placebo in reducing depressive symptoms.
The current study focused on participants' depression and health status, independent of sertraline.
"We wanted to dig deeper into the health effects in patients whose depression improved over the study period, regardless of their medication use," said Xiong.
Xiong and the research team used data from rigorous, standardized evaluations administered over the course of the 12-week SADHART-CHF study to measure both depression and general health. The Hamilton Depression Rating Scale questionnaire was administered periodically to all study participants to assess the severity of depressive symptoms. Cardiac and general health were determined using the Kansas City Cardiomyopathy Questionnaire and the Short Form Health Survey (completed by 285 study participants) and a six-minute walk test (completed by 378 participants).
Participants whose depression remitted during the trial intervention had improvement on scores of physical health on a variety of measures, including social limitation, physical limitation, quality of life, symptom frequency and total symptoms.
"To put the results in perspective, a five-point change in the Kansas City Cardiomyopathy Questionnaire is clinically significant," says Xiong. "The patients whose depression was in remission had scores 13 points higher than those who were not in remission."
Those outcomes were backed up by the Short Form Health Survey, which showed that reduced depression symptoms also improved physical function and general health perception. The six-minute walk test also showed significant improvements in endurance, as patients with reduced depression could walk on average 47 meters -- or about 154 feet -- farther than their counterparts with major depression.
According to the researchers, their results open up a new avenue of investigation that could lead to therapies that leverage the connections between the mind and the body and help heart-failure patients stabilize their condition.
"Our new study is just the tip of the iceberg, since the relationship between the body and mind is extremely complex," said Wei Jiang, senior author of the study and director of the Neuropsychocardiology Laboratory at Duke University Medical Center.
"Researchers and practitioners increasingly recognize that the mind and the body have powerful connections, which is promising since they have been segregated for years," Jiang added. "This kind of interdisciplinary research can help find answers to how physical health affects mental health, and vice versa, and inform the development of clinical practices that recognize this approach."
Xiong and Jiang also recommend further research to delineate why some patients respond to depression medications while others do not.
"There may be underlying genetic or other physiological differences, such as inflammatory markers, that alter the opportunities for treatments to work optimally," said Xiong. "Knowing that relieving depression can be accompanied by broad physical health benefits, we want to be able to identify ways to make treatment modalities as helpful as possible for as many people as possible, especially for those with serious heart disease."