Delirium among older adults living at home: a systematic review of prevalence, incidence, and risk factors

Abstract

Background Delirium will occur more often in community-dwelling adults as the population ages, increasing the a priori risk. Aim To detearmine delirium prevalence and incidence among older adults living at home. The secondary aim was to examine delirium risk factors in this population. Design and setting This was a systematic review guided by the Joanna Briggs Institute Manual for Evidence Synthesis. Method PubMed/Medline, CINAHL, Embase, and Google Scholar were searched from inception to November 2024. Studies reporting delirium prevalence, incidence rate, or risk factors in individuals aged ≥65 years and residing at home were selected. Studies about delirium caused by alcohol or recreational drugs were excluded. Study characteristics, point prevalence, 1-year period prevalence or incidence, and risk factors were extracted and analysed. Results Twenty-four studies were identified. The delirium prevalence rate was 0.2–8.3% in older community-dwelling adults, 1.4–44.1% in indviduals who were frail and received home care or who consulted a GP, and 16.0–27.0% in individuals referred for outpatient psychogeriatric care. The 1-year period prevalence and incidence was 0.0–5.8%. Studies that employed a delirium-specific instrument reported higher rates than studies based on routinely collected healthcare data. Twelve of the included studies examined 22 risk factors for delirium. A statistically significant association was found consistently with frailty, but not with demographics, medical history, or other factors. Conclusion Delirium prevalence rates were substantial in community-dwelling older adults who were frail and people referred for outpatient psychogeriatric care. Studies relying on routine healthcare data showed the lowest prevalence rates, which suggests that delirium is often missed or not registered.