Social isolation among individuals ages 65 years and older is associated with poor health outcomes. However, little is known about health care utilization patterns of socially isolated individuals. This retrospective, observational study evaluated associations between social isolation and hospital and emergency department (ED) utilization among Medicare patients ages 65 years and older. In a cohort of 18,557 Medicare members age 65 years and older at Kaiser Permanente Northwest, the authors compared rates of hospitalization and ED visits in the 12 months following a baseline survey between respondents who reported feeling lonely or socially isolated and those who did not, controlling for demographic and health variables and utilization in the 12 months prior to the survey. Statistical analysis was conducted in February 2020. In adjusted models, those who reported "sometimes" experiencing social isolation were more likely to have at least 1 hospital admission (odds ratio [ORsometimes]: 1.17, 95% confidence interval [CI]: 1.01-1.35, P = 0.04), than those who "rarely" or "never" experienced social isolation. Those who experienced social isolation "sometimes" or "often/always" were more likely to have at least 1 ED visit (ORsometimes: 1.28, 95% CI: 1.15-1.41, P < 0.0001, and ORoften/always: 1.51, 95% CI: 1.25-1.84, P < 0.0001, respectively) than those who "rarely" or "never" experienced social isolation. These findings suggest that self-reported social isolation may be predictive of future hospital admissions and ED utilization. Research is needed to determine how addressing social isolation needs within the health care system affects health care utilization and health outcomes.
Keywords: Medicare; health care utilization; social determinants of health (SDH); social isolation.