Adverse Outcomes After Hospitalization and Delirium in Persons With Alzheimer Disease

BACKGROUND: Hospitalization, frequently complicated by delirium, can be a life-changing event for patients with Alzheimer disease (AD). OBJECTIVE: To determine risks for institutionalization, cognitive decline, or death associated with hospitalization and delirium in patients with AD. DESIGN: Prospective cohort enrolled between 1991 and 2006 into the Massachusetts Alzheimer's Disease Research Center (MADRC) patient registry. SETTING: Community-based. PARTICIPANTS: 771 persons aged 65 years or older with a clinical diagnosis of AD. MEASUREMENTS: Hospitalization, delirium, death, and institutionalization were identified through administrative databases. Cognitive decline was defined as a decrease of 4 or more points on the Blessed Information-Memory-Concentration test score. Multivariate analysis was used to calculate adjusted relative risks (RRs). RESULTS: Of 771 participants with AD, 367 (48%) were hospitalized and 194 (25%) developed delirium. Hospitalized patients who did not have delirium had an increased risk for death (adjusted RR, 4.7 95% CI, 1.9 to 11.6) and institutionalization (adjusted RR, 6.9 CI, 4.0 to 11.7). With delirium, risk for death (adjusted RR, 5.4 CI, 2.3 to 12.5) and institutionalization (adjusted RR, 9.3 CI, 5.5 to 15.7) increased further. With hospitalization and delirium, the adjusted RR for cognitive decline for patients with AD was 1.6 (CI, 1.2 to 2.3). Among hospitalized patients with AD, 21% of the incidences of cognitive decline, 15% of institutionalization, and 6% of deaths were associated with delirium. LIMITATIONS: Cognitive outcome was missing in 291 patients. Sensitivity analysis was performed to test the effect of missing data, and a composite outcome was used to decrease the effect of missing data. CONCLUSION: Approximately 1 in 8 hospitalized patients with AD who develop delirium will have at least 1 adverse outcome, including death, institutionalization, or cognitive decline, associated with delirium. Delirium prevention may represent an important strategy for reducing adverse outcomes in this population.