Cognitive, functional, and behavioral decline associated with polypharmacy and potentially inappropriate medication use in community-dwelling elders with and without dementia

OBJECTIVES: 1) To determine the relationship between polypharmacy and potentially inappropriate medication use (PIRx) with cognitive/functional/behavioral decline. 2) To examine whether these relationships differ among older adults with and without dementia. METHODS: Baseline and follow-up data (9/2005-9/2007) from 29 U.S. Alzheimer's Disease Centers were obtained from the National Alzheimer's Coordinating Center Uniform Data Set. We included 1,303 (728=demented, 575=non-demented) community-dwelling persons aged ≥65 who reported taking ≥1 prescription medication at both visits. We defined PIRx with 2003 Beers criteria, cognition with Clinical Dementia Rating, function with a single item regarding level of dependence, and 12 behavioral problems from the Neuropsychiatric Inventory-Questionnaire. Stratified by dementia diagnosis, generalized linear mixed models were performed on complete cases, adjusting for age, sex, and chronic comorbid conditions. RESULTS: Subjects with dementia taking high number of medications were more likely to exhibit cognitive and functional decline but not worsening behaviors. However, those taking PIRx were less likely to exhibit cognitive decline. Subjects without dementia taking high number of medications were more likely to exhibit functional decline and worsening depression. Those taking PIRx were not more likely to exhibit any decline. CONCLUSION: Polypharmacy is associated with worse health outcomes in community-dwelling older adults with and without dementia but little evidence suggests that PIRx contributed to the observed decline. The validity of using Beers criteria to define PIRx deserves further investigation in older adults with dementia.