ObjectivesSocial isolation has been linked to poor survival in patients with coronary artery disease (CAD). Few studies have closely examined the psychosocial characteristics of CAD patients who lack social contact.MethodsSocial isolation was examined as a predictor of mortality in 430 patients with significant CAD. More isolated patients were compared with their less isolated counterparts on factors that might help explain the association between isolation and survival.ResultsThe mortality rate was higher among isolated individuals. Those with three or fewer people in their social support network had a relative risk of 2.43 (p= .001) for cardiac mortality and 2.11 (p= .001) for all-cause mortality, controlling for age and disease severity. Adjustments for income, hostility, and smoking status did not alter the risk due to social isolation. With the exception of lower income, higher hostility ratings, and higher smoking rates, isolated patients did not differ from nonisolated patients on demographic indicators, disease severity, physical functioning, or psychological distress. Isolated patients reported less social support and were less pleased with the way they got along with network members, but they did not report less satisfaction with the amount of social contact received.ConclusionsPatients with small social networks had an elevated risk of mortality, but this greater risk was not attributable to confounding with disease severity, demographics, or psychological distress. These findings have implications for mechanisms linking social isolation to mortality and for the application of psychosocial interventions.