Prospective observational study of delirium recovery trajectories and associated short-term outcomes in older adults admitted to a specialized delirium unit

Abstract

Objectives: To describe the recovery trajectories of delirium and to determine factors predicting the course of recovery and adverse outcome.

Design: A prospective observational study.

Setting: Geriatric monitoring unit (GMU), a five-bed unit specializing in managing older adults with delirium.

Participants: Individuals admitted to the GMU between December 2010 and August 2012 (N = 234; mean age 84.1 ± 7.4).

Measurements: Information was collected on demographic characteristics; comorbidities; severity of illness; functional status; and daily cognitive, Delirium Rating Scale, Revised-98 (DRS-R98) severity, and functional scoring. Resolution of delirium, and thus GMU discharge, was determined according to clinical assessment. The primary outcome was residual subsyndromal delirium (SSD) (DRS-R98 severity ≥13) upon GMU discharge. Univariate and multivariate methods were used to determine the predictors of residual SSD and adverse outcomes (inpatient mortality and incident nursing home admission upon discharge).

Results: Participants with residual SSD had a slower recovery in terms of delirium severity, cognition, and functional status than those with no residual SSD. Residual SSD predictors included underlying dementia, admission DRS-R98 severity, DRS-R98 severity on Day 1 minus Day 3 of GMU stay, and admission modified Barthel Index. Only presence of residual SSD at discharge predicted adverse outcomes (odds ratio = 5.27, 95% confidence interval = 1.43-19.47).

Conclusion: Individuals with residual SSD had prolonged recovery trajectory of delirium. These new insights into the recovery trajectories of delirium may help formulate early discharge planning and provide the basis for future research on delirium treatment.

Keywords: mortality; outcomes; subsyndromal delirium.