• delirium;
  • aged;
  • prognosis;
  • longitudinal;
  • dementia

OBJECTIVES: To describe the clinical course and outcomes of delirium up to 12 months after diagnosis, the relationship between the in-hospital clinical course and post-discharge outcomes, and the role of dementia in both the clinical course and outcomes of delirium.

DESIGN: Prospective cohort study.

SETTING: Medical wards of a 400-bed, university-affiliated, primary acute care hospital in Montreal.

PATIENTS: Cohort of 193 medical inpatients aged 65 and over with delirium diagnosed at admission or during the first week in hospital, who were discharged alive from hospital.

MEASUREMENTS AND MAIN RESULTS: Study outcomes included cognitive impairment and activities of daily living (standardized, face-to-face clinical instruments at 1-, 2-, 6-, and 12-month follow-up), and mortality. Dementia, severity of illness, comorbidity, and sociodemographic variables were measured at time of diagnosis. Several measures of the in-hospital course of delirium were constructed. The mean numbers of symptoms of delirium at diagnosis and 12-month follow-up, respectively, were 4.5 and 3.5 in the subgroup of patients with dementia and 3.4 and 2.2 among those without dementia. Inattention, disorientation, and impaired memory were the most persistent symptoms in both subgroups. In multivariate analyses, pre-morbid and admission level of function, nursing home residence, and slower recovery during the initial hospitalization were associated with worse cognitive and functional outcomes but not mortality.

CONCLUSIONS: Among patients with and without dementia, symptoms of delirium persist up to 12 months after diagnosis. Quicker in-hospital recovery is associated with better outcomes.