Persistent Delirium Predicts Greater Mortality

OBJECTIVES: To examine the association between persistent delirium and 1-year mortality in newly admitted post-acute care (PAC) facility patients with delirium who were followed regardless of residence. DESIGN: Observational cohort study. SETTING: Eight greater-Boston skilled nursing facilities specializing in PAC. PARTICIPANTS: Four hundred twelve PAC patients with delirium at admission after an acute hospitalization. MEASUREMENTS: Assessments were done at baseline and four follow-up times: 2, 4, 12, and 26 weeks. Delirium, defined using the Confusion Assessment Method, was assessed, as were factors used as covariates in analyses: age, sex, comorbidity, functional status, and dementia. The outcome was 1-year mortality determined according to the National Death Index and corroborated using medical record and proxy telephone interview. RESULTS: Nearly one-third of subjects remained delirious at 6 months. Cumulative 1-year mortality was 39%. Independent of age, sex, comorbidity, functional status, and dementia, subjects with persistent delirium were 2.9 (95% confidence interval=1.9–4.4) times as likely to die during the 1-year follow-up as subjects whose delirium resolved. This association remained strong and significant in groups with and without dementia. Additionally, when delirium resolved, the risk of death diminished thereafter. CONCLUSION: In patients who were delirious at the time of PAC admission, persistent delirium was a significant independent predictor of 1-year mortality.