“This study is an important first step in our quest to understand how to reduce heart disease risk by treating depression and social isolation. Although we did not see the hoped-for reduction in deaths and heart attacks, it is encouraging that the treated patients felt better and experienced improved social relationships,” said NHLBI Director Claude Lenfant, M.D. “We still know from other studies that depression and low social support in heart disease patients are risk factors for mortality. That is why it is important to analyze these results and to conduct further research so we can reduce deaths and heart attacks.”
The Enhancing Recovery in Coronary Heart Disease Patients Study (ENRICHD) is the first major study to evaluate the effects of treating depression and low social support in patients who have had a heart attack. An estimated 25 percent of heart disease patients have either depression or low social support after a heart attack. Heart disease patients who have either one of these risk factors have a 3 to 4 times higher risk of death.
The scientists who conducted ENRICHD suggest that the lack of effect on heart disease deaths and heart attacks may be related to the fact that both groups of patients studied had less depression and increased social support after participating in the trial. Of the two groups of patients compared in the study, only one received 6 months of psychological counseling. This group showed the greatest improvement in psychosocial measures. The other group assigned to “usual medical care” also showed improvement in depression and social support, although to a lesser degree. According to the ENRICHD investigators, the difference between groups may not have been large enough to have an impact on deaths and number of heart attacks.
Allan S. Jaffe, M.D., ENRICHD study co-chair, cardiologist, and Professor of Medicine at the Mayo Clinic, Rochester, Minnesota, said there are several possible explanations why the patients in the usual medical care group improved almost as much as the treated group.
“These patients may have gotten treatment on their own, benefitted from being in the study per se, or they may have only been depressed for a short time and then spontaneously improved,” he said. “We won’t know for sure until we analyze this further.”
ENRICHD enrolled 2, 481 patients at 73 hospitals affiliated with 8 medical centers around the country. The patients were recruited within 28 days of a heart attack and had either major or minor depression, low social support or both. The average age of patients was 61 years. Forty-four percent of participants were women and 34 percent were minorities. Patients were given a variety of screening tests to measure depression and low social support, including the Depression Interview and Structured Hamilton (DISH), a structured interview guide developed specifically for the study, and the ENRICHD Social Support Instrument, a 5-item scale based on previously tested social support scales and found to predict death in heart patients.
Patients were randomly assigned to either a “treatment” or “usual medical care” group. Both groups were given written information on risk factors for heart disease. The “treatment” group also received a series of individual and group cognitive behavioral therapy sessions. During these sessions, trained counselors provided cognitive therapy, which seeks to modify or eliminate thought patterns contributing to the patient’s symptoms, and behavioral therapy which helps patients change habits. Therapy was given for 6 months. Patients in the “usual medical care” group received no additional information or care beyond what they would ordinarily receive from their providers. During this time, any patients found to have a high level of depression were referred to a psychiatrist and prescribed antidepressants as needed.
At 6 months, depressed patients in the treatment group scored significantly better than those in the usual medical care group on the Hamilton depression scale (57 percent reduction in depression for the treatment group versus 47 percent reduction for the usual medical care group). Similarly, patients in the treatment group who lacked social support had a 27 percent improvement in social support based on the ENRICHD Social Support Instrument (ESSI) compared to an 18 percent improvement in the usual medical care group.
“Treated patients reported less depression, and rated their experience of emotional closeness or connection with significant people in their social network as better than did those in the usual medical care group,” said Susan Czajkowski, Ph.D., ENRICHD project officer and a research psychologist at the NHLBI.
“This means patients receiving the treatment had improved psychological and social functioning, and a better quality of life,” added Czajkowski. “Social isolation and depression remain important risk factors for heart disease. It is critical that we learn everything we can from this study so that we can decrease these conditions and improve people’s lives,” said Lisa Berkman, Ph.D., an epidemiologist and professor at the Harvard School of Public Health and chair of ENRICHD.
Despite the treatment group’s improvements in depression and social support, there was no change in heart disease survival. After 3 years, 24.4 percent of the patients in the treatment group had either died or suffered a second heart attack compared to 24.2 of the usual medical care patients.
Jaffe noted that further analysis may shed light on why depression and social support were altered but not deaths or heart attacks. “We may find out that the timing of the treatment should be changed. Treating depression and social support during the medically vulnerable period right after a heart attack may not be the best time to prevent deaths and heart attacks. We may need to intervene earlier – and treat heart disease patients who are depressed before they have a heart attack,” he said.
NHLBI press releases, fact sheets, and other materials are available online at: www.nhlbi.nih.gov