Prevalence of cognitive impairment: results from the MRC trial of assessment and management of older people in the community.

BACKGROUND cognitive impairment is an important part of the diagnostic criteria for dementia. The Mini-Mental State Examination (MMSE) is recommended to test for cognitive impairment and to monitor medication response. OBJECTIVES we examined the prevalence of cognitive impairment in the UK and assessed associations with cognitive impairment. DESIGN cross-sectional survey as part of a cluster randomised trial. SUBJECTS representative sample of people aged 75 years and over. METHODS all subjects had a detailed baseline health assessment including the MMSE. RESULTS a total of 15,051 subjects completed the assessment (71.9%). Almost two-thirds of subjects were female (61.5%) and almost half were aged between 75 and 79 years (47.0%). The prevalence of cognitive impairment was 18.3% (95% confidence intervals (CI) = 16.0-20.9) at a cut-off of 23/24, and 3.3% (95% CI = 2.8-4.0) at 17/18. Those with impairment (MMSE 23/24) were significantly more likely to have hearing (odds ratio (OR) 1.7), vision (OR 1.7) and urinary incontinence problems (OR 1.3), have two or more falls in the previous 6 months (OR 1.4), and report poorer health (OR 1.9). Almost half the participants lived alone (n = 7,073; 47.0%) and of these almost one-fifth were impaired (MMSE 23/24; 19.4%). CONCLUSIONS there was a high prevalence of cognitive impairment. This representative sample demonstrates the potential burden of disease and service demands. It supports the need for a broader assessment of functioning as recommended by the National Service Framework for Older People, particularly in people with cognitive impairment.