Published: Mar. 22, 2001
Updated: Nov. 3, 2004
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By Duke Medicine News and Communications
DURHAM, N.C. - It has been known for some time that social isolation increases the risks of heart patients suffering further from their disease or even dying, but until now researchers didn't have a clear idea of which particular patient characteristics are responsible for these increased risks.
A new study by researchers at Duke University Medical Center has ruled out certain psychosocial and environmental factors thought to be behind the increased risk, and uncovered potential difficulties in finding ways of helping this group of patients.
"For heart patients with small social networks, we found that the increased risks were not attributable to severity of their disease, social status, or whether or not a patient was distressed," said lead researcher Beverly Brummett, who published the results of the Duke team's study today (March 23) in the journal Psychosomatic Medicine.
The research was supported by grants from the National Heart, Lung, and Blood Institute and the National Institute on Aging, both parts of the National Institutes of Health (NIH).
"We expected that these isolated patients would have higher levels of distress -- depression or stress -- but we were surprised to find that this wasn't the case," Brummett continued. "These data suggest that it could be hard for us to get in there and intervene -- the patients appear to be isolated and want to stay that way. They may be resistant if we try to intervene."
The researchers did find that people with a support network of fewer than three were more than twice as likely as patients with larger networks to die from their heart disease during the study's follow-up period, which averaged four years.
The concept of social network is very open-ended. It does not necessarily mean the patients have regular contact with close friends or family members, but any person with whom the patient would have regular contact during the day qualifies as being a part of a social network.
"We asked these patients many different questions in many ways, and still the most isolated people could only come up with two or three people with whom they have interactions," Brummett said. "We're not talking necessarily about confidants or close friends, but just normal human contact, like one would have in the work or social environment."
While many studies have looked at the effects of social isolation on health, the group of patients that Brummett's group analyzed is one of the most well-characterized -- the 430 patients took an exhaustive battery of psychological and psychosocial tests. This allowed researchers to control for a wide variety of environmental, medical and psychological factors.
The researchers described that following characteristics of the isolated patients:
-- They reported fewer than half the number of visits reported by non-isolated patients.
-- More than one-third of the isolated patients averaged less than one network contact every three days.
-- One-fifth of the isolated patients failed to name one person who provides emotional support during everyday life or during a crisis.
-- More than one-third reported no one with whom they could discuss important decisions during a time of crisis.
-- Isolated patients were less likely to be married.
-- Though isolated patients did not differ from non-isolated patients in attending religious services, they did report less participation in other, more social religious activities.
Also, according to Brummett, the isolated patients tended to have lower incomes and tended to smoke more, but after statistical analysis, these environmental factors could not explain the increased risk. Psychologically, the isolated patients tended to be more hostile, but once again this factor did not contribute to the increased risk, she said.
"What we also found so intriguing was that from their own perspectives, most of these isolated patients did not perceive themselves to be socially isolated," Brummett continued. "They seemed content with their level of support. This presents a real challenge for those attempting to develop new approaches to help these patients."
While the current study does not conclusively explain why the most isolated heart patients are at such a high risk of dying from their disease, it does call into question some prevailing views on the role of isolation and mortality, Brummett said. Her analysis demonstrates that the increase in risk is not due to disease severity, socioeconomic status, depression or hostility.
"Further prospective studies are needed to fully understand the interplay of the factors in this phenomenon," Brummett added.
One such study is under way. Duke is in the final year of an NIH-supported, multi-center clinical trial to measure the effects of psychological counseling and group therapy in protecting heart patients from future heart attacks. The trial, known as ENRICHD (Enhancing Recovery in Coronary Heart Disease Patients), enrolled more than 3,000 patients and is the first such trial to investigate the promise of such interventions.
Joining Brummett in her study were Duke colleagues John Barefoot, Ilene Siegler, Nancy Clapp-Channing, Barbara Lytle, Hayden Bosworth, Dr. Redford Williams and Dr. Daniel Mark.