Effect of the overlap syndrome of depressive symptoms and delirium on outcomes in elderly adults with hip fracture: a prospective cohort study

Abstract

Objectives: To analyze the incidence of the overlap syndrome of depressive symptoms and delirium, risk factors, and independent and dose-response effect of the overlap syndrome on outcomes in elderly adults with hip fracture.

Design: Prospective cohort study.

Setting: University hospital.

Participants: Individuals with hip fracture without delirium (N = 277; aged 78.0 ± 8.2) consequently enrolled in a prospective cohort study.

Measurements: Depressive symptoms were assessed using the Geriatric Depression Scale and cognitive status using the Short Portable Mental Status Questionnaire upon hospital admission. Incident delirium was assessed daily during the hospital stay using the Confusion Assessment Method. Information on complications acquired in the hospital, severity of complications, re-interventions, length of hospital stay, and 1-month mortality was recorded.

Results: Thirty (10.8%) participants had depressive symptoms alone, 88 (31.8%) delirium alone, 60 (21.7%) overlap syndrome, and 99 (35.7%) neither condition. According to multivariate regression analysis, participants with the overlap syndrome had significantly higher incidence of vision impairment (P = .02), longer time-to-surgery (P = .03), and lower cognitive function (P < .001) than participants with no depressive symptoms and no delirium. In the adjusted regression analysis, participants with neither condition were at lower risk of complications than those with the overlap syndrome (P = .03). After adjustment, participants with the overlap syndrome were at higher risk of longer hospital stay independently (P = .003) and in a dose-response manner in the following order: no depression and no delirium, depressive symptoms alone, delirium alone, and the overlap syndrome (P = .002).

Conclusion: Depressive symptoms and delirium increase the likelihood of adverse outcomes after hip fracture in a step-wise manner when they coexist. To reduce the risk of adverse outcome in individuals with hip fracture, efforts to identify, prevent, and treat this condition need to be increased.

Keywords: delirium; depressive symptoms; hip fracture; outcomes.