Approximately 13 million American adults have coronary artery disease . The primary goal of treating coronary artery disease, or any chronic disease for that matter, is to improve patients’ health status by reducing their symptom burden, minimizing or avoiding any loss of function, and improving or maintaining their quality of life. In patients with coronary artery disease, cardiovascular interventions are known to improve patients’ health status, however, the extent to which these improvements were the result of cardiac versus noncardiac factors has been unclear.

Indeed, most studies have found only limited associations between physiologic cardiac function and a patient’s health status measures, leaving at least one group of researchers to wonder whether other (noncardiac) factors may be playing an important role in the health status of patients with heart disease.

Depression can affect a person’s heart rhythms, increase blood pressure, and alter the blood’s clotting ability. It can also lead to elevated insulin and cholesterol levels. These risk factors, coupled with increased rates of obesity , form a group of signs and symptoms that often serve as both a predictor of and a response to coronary artery disease.

Recently, a new study set out to compare the contributions of depressive symptoms and measures of cardiac function to the health status of patients with coronary artery disease. The study’s results, which are published in the July 9, 2003 issue of JAMA , find that among patients with coronary artery disease, depressive symptoms are strongly associated with patient-reported health status, including symptom burden, physical limitation, quality of life, and overall health.

About the study

The objective of the Heart and Soul study was to compare the degree to which depressive symptoms and traditional physiologic measures of cardiac function were related to the health status of 1024 adults with stable coronary artery disease.

All subjects were followed from September 2000 to December 2002. For each participant, the researchers recorded baseline data from a medical history interview, a physical examination, an exercise tolerance (stress) test, and a comprehensive health status questionnaire.

The questionnaire was used to assess the participants’ depressive symptoms and to measure their health status, which included symptom burden, physical limitations, and overall quality of life. Based on their responses, participants were categorized as having minimal depressive symptoms (score 0-3), mild to moderate depressive symptoms (score 4-9), and symptoms consistent with major depression (score 10 and above).

Each participant’s cardiac function was also assessed. Researchers used a resting echocardiogram to measure their left ventricular ejection fraction (how effectively their heart was pumping blood), an exercise stress test to determine their tolerance for physical activity, and a stress echocardiogram to determine their degree of ischemia (the degree to which the blood supply to the heart had been reduced by their CAD.

The findings

The researchers found that the participants with depressive symptoms (201 in total) were more likely to report at least mild physical discomfort and physical limitations, and a minimally diminished quality of life than their counterparts who did not have depressive symptoms. Participants with depressive symptoms were also more likely to report that they considered themselves to be in only fair to poor overall health. Indeed, depressive symptoms were found to be independently associated with all four measures of health status.

In contrast, two of the traditional physiologic measures of health status—ejection fraction and ischemia— were not found to be independently associated with any of the four measures of health status.

How does this affect you?

The study concluded that in patients with coronary artery disease, depressive symptoms are strongly associated with four important health status outcomes: symptom burden, physical function, disease-specific quality of life, and overall health. This is in contrast to two commonly used physiologic measures of disease severity in coronary artery disease: ejection fraction and ischemia.

While the results of this study cannot determine the causal link between depressive symptoms and health status, they do suggest that depressive symptoms are an important factor in the health status of patients with coronary artery disease. The researchers, therefore, recommend that efforts by physicians to improve the overall health status of their patients with coronary artery disease should include the assessment and treatment of depressive symptoms. This treatment will help patients manage both their depressive symptoms and their coronary artery disease, thus enhancing survival and quality of life.