Screening for dementia in primary care: a summary of the evidence for the U.S. Preventive Services Task Force.

BACKGROUND: Dementia is a large and growing problem but is often not diagnosed in its earlier stages. Screening and earlier treatment could reduce the burden of suffering of this syndrome.
PURPOSE: To review the evidence of benefits and harms of screening for and earlier treatment of dementia. DATA SOURCES: MEDLINE, PsycINFO, EMBASE, the Cochrane Library, experts, and bibliographies of reviews. STUDY SELECTION: The authors developed eight key questions representing a logical chain between screening and improved health outcomes, along with eligibility criteria for admissible evidence for each question. Admissible evidence was obtained by searching the data sources. DATA EXTRACTION: Two reviewers abstracted relevant information using standardized abstraction forms and graded article quality according to U.S. Preventive Services Task Force criteria. DATA SYNTHESIS: No randomized, controlled trial of screening for dementia has been completed. Brief screening tools can detect some persons with early dementia (positive predictive value < or =50%). Six to 12 months of treatment with cholinesterase inhibitors modestly slows the decline of cognitive and global clinical change scores in some patients with mild to moderate Alzheimer disease. Function is minimally affected, and fewer than 20% of patients stop taking cholinesterase inhibitors because of side effects. Only limited evidence indicates that any other pharmacologic or nonpharmacologic intervention slows decline in persons with early dementia. Although intensive multicomponent caregiver interventions may delay nursing home placement of patients who have caregivers, the relevance of this finding for persons who do not yet have caregivers is uncertain. Other potential benefits and harms of screening have not been studied.
CONCLUSIONS: Screening tests can detect undiagnosed dementia. In persons with mild to moderate clinically detected Alzheimer disease, cholinesterase inhibitors are somewhat effective in slowing cognitive decline. The effect of cholinesterase inhibitors or other treatments on persons with dementia detected by screening is uncertain.