Potentially inappropriate medication use among community-dwelling elderly patients with dementia in U.S. Alzheimer's Disease Centers

OBJECTIVE: To examine the prevalence and patient characteristics associated with potentially inappropriate medication use (PIRx) among elderly patients with dementia. METHODS: Data (9/2005-9/2007) were from the National Alzheimer's Coordinating Center Uniform Data Set, which contained information collected at 29 NIA-funded Alzheimer's Disease Centers across the U.S. This cross-sectional study analyzed 2,665 community-dwelling, dementia patients aged 65+ who took at least one prescription medication. PIRx was defined using the Beers 2003 drugs-to-avoid criteria. Multivariate logistic regressions accounting for center effect were performed. RESULTS: Among the study sample, 20.5% had at least one PIRx (16.7% took 1 PIRx, 3.3% took 2 PIRx, and 0.5% took 3+ PIRx). The five most common PIRx involved benzodiazepines, fluoxetine, digoxin, muscle relaxants/antispasmodics, and nifedipine. Among the primary diagnoses of dementia that had at least 30 patients, primary progressive aphasia and dementia of undetermined etiology had the highest proportion of patients with PIRx, while vascular dementia had no PIRx cases. Patient characteristics associated with higher odds of PIRx were polypharmacy (taking 5+ prescription medications), cardiovascular disease, mild depression, and moderate/severe anxiety. Characteristics associated with lower odds were male, mild cognitive impairment, dependent on others to pay bills, hypercholesterolemia, and living with individuals other than a spouse, relative or friend. CONCLUSION: PIRx is common among community-dwelling elderly patients with dementia. Interventions to improve proper medication use should target at-risk patients, especially those with polypharmacy, cardiovascular disease, depression and anxiety. The impact of PIRx on this population needs further investigation.