Social Disparities, Delirium Occurrence, and Related Outcomes Among Hospitalized Older Adults

Background: Underlying socio-economic and health burden may variably impact delirium presentation among older adults. We characterized differences in patient factors related to social marginalization and studied their effects on delirium occurrence and hospital outcomes. Methods: We conducted a 7-year retrospective analysis of older adults (aged ≥ 70 years) who systematically underwent screening for delirium at an 8-hospital healthcare system. Our primary exposure included patient characteristics related to demographics and social marginalization. Multivariable logistic regression models were built to identify factors associated with increased odds of delirium occurrence, either (1) present-on-admission (D-POA) or (2) hospital-acquired (HAD). Secondary outcomes included hospital length of stay, in-hospital mortality, and discharge disposition. Results: A total of 260,200 older adults were screened for delirium (median [IQR] age in years: 78.0 [74.0–84.0]; female: 143,402 [55.1%]; non-Hispanic Black: 40,737 [15.8%]; Hispanic: 30,760 [11.9%]; median [IQR] Area Deprivation Index: 4.0 [2.0–6.0]; median [IQR] Charlson Comorbidity Index: 10.0 [8.0–13.0]). Rates of D-POA were 25.5% across all screened patients. Among patients delirium-free at admission, 10.4% later acquired HAD. In addition to known risk associations with older age and comorbidity burden, increased odds of D-POA were observed for non-Hispanic Black patients (aOR, 95% CI: 1.49, 1.44–1.54), Hispanic patients (aOR, 95% CI: 1.31, 1.26–1.36), higher ADI-defined socio-economic marginalization (aOR, 95% CI: 1.01, 1.00–1.01), and prior dementia (aOR: 6.53, 6.37–6.68). HAD risks were also higher for males (aOR, 95% CI: 1.07, 1.04–1.11), non-Hispanic Black patients (1.39, 1.32–1.46), Hispanic patients (aOR, 95% CI: 1.28, 1.21–1.35), residence in higher ADI neighborhoods (aOR, 95% CI: 1.02, 1.02–1.03), and prior dementia (aOR, 95% CI: 2.44, 2.34–2.53). Effects of delirium on poor hospital outcomes did not differ by socio-demographic sub-groups. Conclusions: Delirium risks were higher among minoritized and socio-economically marginalized older adults. These findings present an opportunity to consider social marginalization as an important factor in delirium risk stratification.