Prevalence and incidence of delirium in long-term care

(1) To describe the prevalence and 6-month incidence of delirium in long-term care facility (LTCF) residents age 65 and over; (2) To describe differences in these measures by resident baseline characteristics.

A multisite, prospective observational study was conducted in seven LTCFs in the province of Quebec, Canada. Residents of age 65 and over were recruited into two cohorts: Cohort A with a Mini-Mental State Examination (MMSE) score of 10 or more and Cohort B with an MMSE score of less than 10. Baseline resident measurements were obtained from research resident assessments, nurse interviews, and chart review. Weekly resident assessments for up to 24 weeks included the Confusion Assessment Method (CAM).

Two hundred seventy-nine residents were recruited and completed baseline delirium assessments: 204 in Cohort A and 75 in Cohort B. The prevalence of delirium at baseline was 3.4% in Cohort A and 33.3% in Cohort B. The incidence of delirium among those without delirium at baseline (per 100 person-weeks of follow-up) was 1.6 in Cohort A and 6.9 in Cohort B. In multivariate analyses, a diagnosis of dementia, moderate to severe cognitive impairment, and depressive symptoms at baseline were associated with a greater prevalence and incidence of delirium.

Delirium is an important clinical problem in LTCF residents, particularly among those with moderate to severe cognitive impairment at baseline.