Stability of Diagnoses of Cognitive Impairment, Not Dementia in a Veterans Affairs Primary Care Population

Abstract

To describe the stability of cognitive impairment, not dementia (CIND) in a longitudinal cohort of primary care veterans. To examine the association between baseline brief cognitive screening tests, demographic and clinical characteristics, and cognitive decline. Follow-up cognitive assessment after an average of 2.5years of a cohort of veterans in primary care whose baseline status was CIND or normal cognition. Three Department of Veterans Affairs primary care clinics. Subjects with CIND at baseline and a sampling of subjects with baseline normal cognition. Veterans underwent a standard assessment, including neuropsychological tests and informant interview. Of 293 potentially eligible individuals, 186 enrolled in the follow-up study. Of the 131 subjects with a baseline diagnosis of CIND, 16 (12%) progressed to dementia, 88 (67%) continued to have a diagnosis of CIND, and 27 (21%) improved to normal cognition. Of the 55 subjects with a baseline diagnosis of normal cognition, one (2%) progressed to dementia, 17 (31%) progressed to CIND, and 37 (67%) remained cognitively normal. In bivariate analyses, poorer performance on baseline cognitive screening tests was associated with cognitive decline, whereas Framingham Stroke Risk Profile (FSRP) and education were not. Similarly, higher scores on cognitive screening tests were associated with return to normal cognition. In multivariable logistic regression models, lower baseline Mini-Cog and Modified Mini-Mental State scores were associated with cognitive decline, whereas Memory Impairment Screen scores, FSRP, and years of education were not. A minority of subjects had worsening of cognitive function sufficient to change diagnostic category. Over an average of 2.5years, subjects diagnosed with CIND at baseline reverted to normal cognition at a higher rate than progressed to dementia. Cognitive screening tests addressing multiple domains of cognitive impairment were predictive of cognitive decline.