One-year Medicare costs associated with delirium in older hospitalized patients with and without Alzheimer's disease dementia and related disorders.

Introduction: One-year health-care costs associated with delirium in older hospitalized patients with and without Alzheimer's disease and related dementias (ADRD) have not been examined previously.

Methods: Medicare costs were determined prospectively at discharge, and at 30, 90, and 365 days in a cohort (n = 311) of older adults after hospital admission.

Results: Seventy-six (24%) patients had ADRD and were more likely to develop delirium (51% vs. 24%, P < 0.001) and die within 1 year (38% vs. 21%, P = 0.002). In ADRD patients with versus without delirium, adjusted mean difference in costs associated with delirium were $34,828; most of the excess costs were incurred between 90 and 365 days (P = 0.03). In non-ADRD patients, delirium was associated with increased costs at all timepoints. Excess costs associated with delirium in ADRD patients increased progressively over 1 year, whereas in non-ADRD patients the increase was consistent across time periods.

Discussion: Our findings highlight the complexity of health-care costs for ADRD patients who develop delirium, a potentially preventable source of expenditures.

Highlights: Novel examination of health-care costs of delirium in persons with and without Alzheimer's disease and related dementias (ADRD). Increased 1-year costs of $34,828 in ADRD patients with delirium (vs. without). Increased costs for delirium in ADRD occur later during the 365-day study period. For ADRD patients, cost differences between those with and without delirium increased over 1 year. For non-ADRD patients, the parallel cost differences were consistent over time.