Living alone and cardiovascular outcomes: a meta-analysis of 11 cohort studies

To explore whether living alone could increase the risk of cardiovascular outcomes. We searched PubMed, EMBASE, and Web of Science from their inception to 5 October 2020. Cohort studies evaluating the relationship between living alone and cardiovascular outcomes were included. Subgroup analyses were conducted to explore which characteristics would affect the relationship. A total of 13 effect sizes obtained from 11 studies were included and spanned from 1993 to 2019, with 424,286 participants. This study found that living alone increased the risk of cardiovascular outcomes (HR = 1.22, 95% CI: 1.10-1.36, I² = 80.3%, P = 0.000). In subgroup analyses, living alone increased the risk of cardiovascular outcomes in patients from Europe (HR = 1.37, 95% CI: 1.17-1.61, I² = 76.2%, P = 0.000), but not increased in Asia (HR = 1.17, 95% CI: 0.83-1.66, I² = 76.2%, P = 0.000) and multiple regions (HR = 1.02, 95% CI: 0.96-1.08, I² = 0.0%, P = 0.738). For different cardiovascular outcomes, living alone has statistical significance in increasing the risk of cardiovascular mortality (HR = 1.23, 95% CI: 1.05-1.46, I² = 84.0%, P = 0.000) and myocardial infarction (HR = 1.11, 95% CI: 1.02-1.21, I² = 29.6%, P = 0.213). The risk of cardiovascular mortality in men was higher than women (HR = 1.52, 95% CI: 1.24-1.86 vs HR = 1.01, 95% CI: 0.85-1.20; P < 0.05 for interaction). Sensitivity analysis suggested that the results of the meta-analysis were robust. In conclusion, living alone could increase the risk of cardiovascular outcomes and men were more prone to cardiovascular mortality and myocardial infarction.