Prognosis after hospital discharge of older medical patients with delirium.

OBJECTIVE: To determine survival, functional independence, and cognitive performance of older patients 2 years after an episode of delirium.
DESIGN: Descriptive cohort study.
SETTING: General medical wards of a teaching hospital. PATIENTS: Two hundred twenty-nine consecutive patients aged 70 years or older who had been community-dwelling prior to admission. Fifty patients met criteria for delirium (cases); these were compared to patients without delirium (controls). Two-hundred twenty-three patients survived hospitalization (46 cases, 177 controls) Of these, 92% were followed greater than or equal to 2 years. MAIN OUTCOME MEASURES: Vital status, place of residence, activities of daily living (ADL), and cognitive performance were determined by telephone interview of patients or care-givers 2 years after discharge. Independent community living was defined as survivorship outside of an institution and without dependence in any of four basic ADL (bathing, dressing, transfers, eating).
RESULTS: Two-year mortality in the entire population was 39% for cases and 23% for controls (relative risk 1.82, 95% confidence interval 1.04-3.19). Delirium identified those patients at risk for loss of independent community living, even after adjustment for potential confounding variables (adjusted odds ratio 2.56, 95% confidence interval 1.10-5.91). Follow-up cognitive testing in a subset of patients with high baseline performance revealed a greater decline in performance among cases of delirium than controls (P = 0.023).
CONCLUSIONS: Delirium identifies older patients at risk for mortality or loss of independence. Delirium may also identify patients at risk for future cognitive decline.