Association of Social Isolation With Hospitalization and Nursing Home Entry Among Community-Dwelling Older Adults.

Importance: Social isolation is associated with adverse health outcomes, yet its implications for hospitalization and nursing home entry are not well understood.

Objective: To evaluate whether higher levels of social isolation are associated with overnight hospitalization, skilled nursing facility stays, and nursing home placement among a nationally representative sample of community-dwelling older adults after adjusting for key health and social characteristics, including loneliness and depressive symptoms.

Design, Setting, And Participants: This observational cohort study included 7 waves of longitudinal panel data from the Health and Retirement Study, with community-dwelling adults aged 65 years or older interviewed between March 1, 2006, and June 30, 2018 (11 517 respondents; 21 294 person-years). Data were analyzed from May 25, 2022, to May 4, 2023.

Main Outcomes And Measures: Social isolation was measured with a multidomain 6-item scale (range, 0-6, in which a higher score indicates greater isolation). Multivariate logistic regressions were performed on survey-weighted data to produce national estimates for the odds of self-reported hospitalization, skilled nursing facility stays, and nursing home placement over time.

Results: A total of 57% of this study's 11 517 participants were female, 43% were male, 8.4% were Black, 6.7% were Hispanic or Latino, 88.1% were White, 3.5% were other ("other" includes American Indian or Alaska Native, Asian or Pacific Islander, and other race, which has no further breakdown available because this variable was obtained directly from the Health and Retirement Study), and 58.2% were aged 65 to 74 years. Approximately 15% of community-dwelling older adults in the US experienced social isolation. Higher social isolation scores were significantly associated with increased odds of nursing home placement (odds ratio, 2.01; 95% CI, 1.21-3.32) and skilled nursing facility stays (odds ratio, 1.16; 95% CI, 1.06-1.28) during 2 years. With each point increase in an individual's social isolation score, the estimated probability of nursing home placement or a skilled nursing facility stay increased by 0.5 and 0.4 percentage points, respectively, during 2 years. Higher levels of social isolation were not associated with 2-year hospitalization rates.

Conclusions And Relevance: This cohort study found that social isolation was a significant risk factor for nursing home use among older adults. Efforts to deter or delay nursing home entry should seek to enhance social contact at home or in community settings. The design and assessment of interventions that optimize the social connections of older adults have the potential to improve their health trajectories and outcomes.