"We weren't surprised to find depressive symptoms were associated with how patients felt. But, we were surprised to find that how patients felt was not associated with the two measures of heart disease severity," said Mary A. Whooley, MD, senior author of the study, a physician in general internal medicine at the San Francisco VA Medical Center (SFVAMC) and UCSF assistant professor of medicine and epidemiology and biostatistics.
"These results are telling us that how patients feel may not be as closely associated with their measurable, physical symptoms as we once believed. Therefore, efforts to improve health status and quality of life in patients with cardiac disease should include a focus on depressive symptoms," Whooley said.
The study appears in the July 9 issue of the Journal of the American Medical Association.
The current findings are the latest to come out of the Heart and Soul Study, an ongoing, observational study of a cohort of patients with heart disease living in the San Francisco Bay Area. The ultimate goal of the study, led by Whooley, is to determine whether psychosocial factors influence disease progression in patients with coronary disease. For the current study, Whooley and her colleagues recruited a total of 1,024 participants with stable coronary artery disease from outpatient clinics in the area between September 2000 and December 2002.
Researchers measured depressive symptoms using the Patient Health Questionnaire (PHQ). To determine the severity of heart disease, they utilized two traditional measures. The first, left ventricular ejection fraction, represents the heart's pumping strength. The second, exercise-induced cardiac ischemia, indicates blood flow to the heart during exercise.
Of the 1,024 participants, 20 percent (201) had depressive symptoms. After accounting for such variables as gender and age, researchers found that these patients were more likely than their counterparts to report lower health status, including more frequent chest pain (angina), physical limitation caused by their illness, worse overall health and worse quality of life. Even after accounting for the severity of heart disease, the researchers found that depressed patients were still more likely to report lower health status than their counterparts.
These results suggest that helping cardiac patients feel better may require that physicians do more than prescribe drugs or recommend traditional therapies that improve the health of their hearts. "If we want to improve quality of life for these patients, we have to treat depression, not just work towards improving measures of cardiac function," Whooley said.
Participants who were found to have high levels of depressive symptoms were informed that they may be depressed, instructed to discuss these symptoms with their regular doctor, and provided a list of local resources available for further evaluation and treatment. According to Whooley, previous studies have shown that less than one-half of depressed patients are offered treatment and only about one-quarter end up receiving appropriate treatment.
Whooley and her colleagues are in the middle of an additional three-year follow-up study of the patients involved in this part of the Heart and Soul Study. "We want to know if depression leads to more cardiac events and, if so, what other factors contribute to that," Whooley said.
Additional authors included first author and SFVAMC clinical research fellow Bernice Ruo, MD; SFVAMC data analyst Haiying Liu, MD, MPH; John S. Rumsfeld, MD, PhD; Mark A. Hlatky, MD; and Warren S. Browner, MD, MPH.
Journal
JAMA