PREDICTING LONGITUDINAL DECLINE IN INSTRUMENTAL ACTIVITIES OF DAILY LIVING IN PATIENTS WITH ALZHEIMER’S DISEASE
Grabyan, Jonathan M.
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Appropriate planning for the future functional decline of patients with Alzheimer’s disease (AD) is very important. An easy-to-utilize, reliable method for predicting progression of deficits in instrumental activities of daily living (IADL) would have great clinical utility. The literature predicting functional decline is sparse. This study sought to validate a “pre-progression” estimate of functional decline (rate of annual decline prior to AD diagnosis) for use in predicting future functional decline. Broader analyses of baseline correlates and future predictors of IADLs were also performed. Participants were 785 AD patients enrolled in the Alzheimer’s Disease and Memory Disorders Center (ADMDC) at Baylor College of Medicine. Linear mixed-effects models were utilized to predict the decline over time in IADLs from baseline information. The IADL pre-progression estimate was found to significantly predict future rate of decline even after covariates of age, education, sex, and baseline dementia severity were taken into account. However, the direction of the effect, with lower pre-progression rates predictive of faster decline, was reverse of what was hypothesized. Older Age and more neuropsychiatric symptoms at baseline were significantly predictive of faster future decline (though with a negligible effect size), while MMSE scores and neuropsychological tests results were not. Multiple regressions were used to examine the baseline correlates of IADL performance. Age, MMSE, neuropsychological domains (except motor), and neuropsychiatric symptoms were significantly related to greater IADL impairment at baseline. In summary, there is a disparity between baseline relationships with IADL impairment and ability to predict future IADL decline. Due to the reversed direction of the expected effect, the pre-progression estimate of IADLs was not deemed a valid tool for predicting future decline in functional ability.