Background: Living alone, a proxy for social support, has been inconsistently linked with cardiovascular risk.
Methods: We investigated whether living alone was associated with increased mortality and cardiovascular risk in the global REduction of Atherothrombosis for Continued Health (REACH) Registry. Stable outpatients at risk of or with atherothrombosis were recruited from December 1, 2003, through December 31, 2004, and followed up to 4 years for cardiovascular events. Events were examined by living arrangement with risk adjustment for age, sex, clinical risk factors, therapy, preexisting vascular disease, and sociodemographic factors. Effect modification was tested by age, sex, employment, ethnicity, education, and geography.
Results: Among the 44 573 REACH participants, 8594 (19%) were living alone. Living alone was associated with higher 4-year mortality (14.1% vs 11.1%) and cardiovascular death (8.6% vs 6.8%; log-rank P < .01 for both comparisons); however, there was significant effect modification by age (P value for interaction = .03). Specifically, among younger participants, living alone compared with those living with others was associated with higher mortality (age 45-65 years: 7.7% vs 5.7%; adjusted hazard ratio [HR], 1.24 [95% CI, 1.01-1.51]; age 66-80 years: 13.2% vs 12.3%; adjusted HR, 1.12 [95% CI, 1.01-1.26]), but this was not observed among older participants (age > 80 years: 24.6% vs 28.4%; adjusted HR, 0.92 [95% CI, 0.79-1.06]). A similar trend was observed for the risk of cardiovascular death.
Conclusions: In an international outpatient population with atherothrombosis aged 45 years or older, living alone was associated with increased mortality among all but the most elderly patients, although this observation warrants confirmation.