Differences in functional impairment across subtypes of dementia

Abstract

Background. Dementia is a cause of disability in later life. Despite the importance of functional status to the diagnosis of dementia, limited information exists on differences in functional limitations by dementia subtype. We conducted a cross-sectional analysis using the Aging, Demographics, and Memory Study (ADAMS) to determine the extent of functional impairment among older adults with dementia due to different etiologies. Methods The ADAMS sample consisted of 856 individuals aged 71 years and older originally surveyed as part of the Health and Retirement Study. Based on a comprehensive in-person cognitive evaluation, respondents were assigned to diagnostic categories of normal cognition, cognitive impairment not demented, and demented. Dementia subtypes were grouped into three categories: vascular dementia (VaD), Alzheimer's dementia (AD), and dementia due to other etiologies. For 744 of the 856 respondents, a proxy informant completed a questionnaire asking whether the respondent had difficulty completing instrumental activities of daily living and activities of daily living (ADLs). Results Of 744 ADAMS participants, 263 had dementia: 199 (70.5%) with AD, 42 (16.9%) with VaD, and 22 (12.6%) were demented due to other etiologies. After adjustment for demographics, chronic illnesses, and dementia severity, participants with VaD (odds ratio [OR] 5.74; 95% confidence interval [CI] 2.60-12.69) and other etiologies of dementia (OR 21.23; 95% CI 7.25-62.16) were more likely to have greater than or equal to four ADL limitations compared with those with AD. Conclusions VaD is associated with significantly more ADL limitations than AD. These physical limitations should be considered when designing adult day care programs, which adequately accommodate the needs of non-AD patients. © The Author 2009. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved.