Objective To evaluate cardiovascular (CV) outcomes in outpatients with coronary artery disease (CAD) living alone compared with those living with others.

Methods The prospeCtive observational LongitudinAl RegIstry oF patients with stable coronarY artery disease (CLARIFY) included outpatients with stable CAD. CLARIFY enrolled participants in 45 countries from November 2009 to July 2010, with 5 years of follow-up. Living arrangement was documented at baseline. The primary outcome was a composite of major adverse cardiovascular events (MACEs) defined as CV death, myocardial infarction (MI) and stroke.

Results Among 32 367 patients, 3648 patients were living alone (11.3%). After multivariate adjustment, there were no residual differences in MACE among patients living alone compared with those living with others (HR 1.04, 95% CI 0.92 to 1.18, p=0.52); however, there was significant heterogeneity in the exposure effect by sex (P_interaction<0.01). Specifically, men living alone were at higher risk for MACE (HR 1.17, 95% CI 1.002 to 1.36, p=0.047) as opposed to women living alone (HR 0.82, 95% CI 0.65 to 1.04, p=0.1), predominantly driven by a heterogeneous effect by sex on MI (P_interaction=0.006). There was no effect modification for MACE by age group (P_interaction=0.3), although potential varying effects by age for MI (P_interaction=0.046) and stroke (P_interaction=0.05).

Conclusions Living alone was not associated with an independent increase in MACE, although significant sex-based differences were apparent. Men living alone may have a worse prognosis from CV disease than women; further analyses are needed to elucidate the mechanisms underlying this difference.

Trial registration number ISRCTN43070564.