Correlates of institutionalization among the oldest old-Evidence from the multicenter AgeCoDe-AgeQualiDe study

Objectives There is a lack of studies identifying the correlates of institutionalization specifically among the oldest old. Therefore, our aim was to fill this gap in knowledge. Methods Cross-sectional data (Follow up wave 9; n = 633 observations in the analytical sample) were used from the multicenter prospective cohort study "Needs, health service use, costs and health-related quality of life in a large sample of oldest-old primary care patients (85+)" Correlates of institutionalization among the oldest old-Evidence from a multicenter cohort study. The sample consists of primary care patients aged 86 years and over (mean 90.5 years, SD: 2.9 years). Sociodemographic and health-related independent variables were included in our regression model. Institutionalization was defined as living in a nursing home or an old-age home (not including assisted living facilities). Results Out of the 633 participants, 502 individuals (79.3%) did not live in an institutionalized setting, whereas 73 individuals (20.7%) lived in an institutionalized setting. Multiple logistic regressions showed that the likelihood of institutionalization increased with being divorced/widowed/single (compared to being married; OR: 5.35 [95% CI: 1.75-16.36]), the presence of social isolation (OR: 2.07 [1.20-3.59]), more depressive symptoms (OR: 1.11 [1.01-1.23]), increased cognitive impairment (OR: 1.67 [1.31-2.15]) and higher levels of frailty (OR: 1.48 [1.07-2.06]). Conclusion The study findings identified various sociodemographic and health-related factors associated with institutionalization among the oldest old. Longitudinal studies are required to gain further insights into these associations.