DURHAM, N.C. -- People who are depressed have an increased risk of dying from heart failure, and a new study by Duke University Medical Center researchers may help explain why.
Analyzing more than 1,000 depressed patients with heart failure, the researchers found that it was the depression itself, not the patients' use of antidepressant medications that increased mortality risk.
The finding may provide additional evidence for the current national debate over whether the increased mortality seen in heart failure patients with depression is due to the depression itself or the medications prescribed to treat it, the researchers said.
The researchers, led by internist and psychiatrist Wei Jiang, M.D., said the finding also should help convince physicians who care for heart failure patients to pay closer attention to their patients' mental status, since these patients may be helped by aggressive therapies that target heart problems and depression. Jiang said many physicians who treat heart disease patients continue to pay too little attention to managing their depression.
"In our analysis, we found that heart failure patients who were depressed had 15 percent higher rate of death than those who were not depressed," said Jiang, who presented the results of the study on Monday, Nov. 13, at the annual scientific sessions of the American Heart Association, in Chicago. "Although patients who were taking antidepressants during the first admission to the hospital were more likely to die than the patients who were not taking antidepressants, the association was confounded by existence of depression.
She said that it is the depression, not the use of antidepressants, especially the newest class of antidepressants known as selective serotonin reuptake inhibitors that negatively affected the prognosis of patients with heart failure.
"The results provide further evidence that physicians who take care of heart failure patients must not only prescribe antidepressants to them as the treatment of their depression, but also continue to follow those patients closely," Jiang said. "Depression must be considered a serious risk factor in heart failure."
The study was supported by the National Institute of Mental Health and by an American Psychiatric Institute Research in Education/Merck Early Academic Career Research Award.
Heart failure, also known as congestive heart failure, is marked by the inability of the heart muscle to pump enough oxygen and nutrients in the blood to the body's tissues. Despite its name, not everyone dies immediately and many live for years.
A variety of factors can cause heart failure, including infections of the heart, coronary artery disease, high blood pressure, previous heart attacks and malfunctioning heart valve. An estimated 4.7 million Americans have heart failure, with 400,000 new cases reported each year, and it is the only cardiovascular disease that is rising in incidence, according to the researchers.
For their analysis, Jiang and colleagues examined the medical records of 1,006 heart failure patients who were hospitalized at Duke from March 1997 to June 2003 and asked them to rate their depressive symptoms by an easily administered questionnaire. During the first admission, 30 percent of the patients were depressed and 16.1 percent were taking antidepressants, Jiang said.
The patients in the study were followed for an average of two years and seven months, and Jiang's team found that 42.7 percent of the patients died during the follow-up period. This mortality rate is in line with national averages, Jiang said, adding that approximately 50 percent of all heart failure patients die within five years of being diagnosed.
Jiang said many cardiologists and primary care physicians who treat heart failure patients may be unfamiliar with the typical psychological assessments that can be used to evaluate patients for depression, or they may consider themselves too busy to include such assessments in their regular practice. Physicians who are uncomfortable with treating depression should refer those patients to a psychiatrist, she said.
"Probably only half of the physicians who treat heart failure patients feel comfortable about treating patients for their depression," Jiang said. "Also, those physicians that do prescribe antidepressants shouldn't just write the prescription and see the patients three or six months later."
Not only should more physicians treat their depressed patients for their disease, or at least refer them to a specialist for treatment, but physicians also should ensure that the patients receive adequate follow-up attention, Jiang said.
"Physicians need to know if their patients are experiencing side effects of their medication, or if the initial dose is correct," she said. "In some patients, it can take some time finding the right antidepressant and the proper dose. Also, treating physicians need to know that their patients are continuing to take their medications, and that requires regular follow-up."
Although this and other studies have demonstrated links between depression and worse outcomes for patients with cardiovascular disease, the mechanisms behind the correlation are not well understood, Jiang said. Among possible factors, depressed patients are known to have overly active immune systems, a decrease in the ability of their blood platelets to clot properly and a decrease in their heart's ability to react appropriately to the stresses of everyday life, she said.
"We also know that depressed patients tend not to comply with their treatments, are not as motivated to stick with exercise or rehabilitation programs, and often miss doctor's appointments" Jiang said. "Also, depressed patients tend to make unhealthy lifestyle choices in such areas as diet and smoking."
Jiang said she is investigating ways to improve how health care providers without psychiatric backgrounds can manage depression in heart patients, including finding ways to boost providers' confidence that they can appropriately manage such patients. She and her Duke colleagues have also been conducting a clinical trial investigating whether selective serotonin reuptake inhibitors will improve the cardiac prognosis of heart failure patients with depression. They are currently recruiting patients to the study and hope to publish the results of the study in middle of 2008.
"Many times it can be impractical to make sure every patient with heart failure sees a psychiatrist," Jiang said. "That is why it is so important to improve the knowledge and confidence of nonpsychiatric professionals for care of depression."
Other researchers involved in the study were Maragatha Kuchibhatla, Greg Clary, Michael Cuffe, Eric Christopher, Jude Alexander, Christopher O'Connor, Robert Califf, and Ranga Krishnan.