A systematic review of the prevalence, associations and outcomes of dementia in older general hospital inpatients

Background: Older people are commonly admitted to the acute hospital and increasing numbers will have dementia. In this study we systematically reviewed the prevalence, associations and outcomes of dementia in older people in the general hospital, to examine the range of diagnostic tools used and highlight gaps in the literature. Methods: We searched the English language literature using Embase, PsychInfo and Medline. Studies were included if they used validated criteria for diagnosing dementia, involved subjects over the age of 55 years and were set in the general hospital. Results: Fourteen papers were identified. Prevalence estimates for dementia in studies with robust methodology were 12.9-63.0%. Less than a third of studies screened for delirium or depression and therefore some subjects may have been misclassified as having dementia. The data were highly heterogeneous and prevalence estimates varied widely, influenced by study setting and demographic features of the cohorts. Patients with dementia in the acute hospital are older, require more hours of nursing care, have longer hospital stays, and are more at risk of delayed discharge and functional decline during admission. Conclusions: When planning liaison services, the setting and demographic features of the population need to be taken into account. Most study cohorts were recruited from medical wards. More work is required on the prevalence of dementia in surgical and other specialties. A wider range of associations (particularly medical and psychiatric comorbidity) and outcomes should be studied so that care can be improved.