Is drug use by the elderly with cognitive impairment influenced by type of dementia?

Patterns of drug use among the elderly vary greatly depending on level of cognitive function, yet no systematic evaluation of drug use by type of dementia has been performed. We compared patterns of drug use among patients with Alzheimer's disease (AD) and vascular dementia (VaD) to examine their relation to cognitive impairment. We used a population-based data set with over 350,000 residents admitted between 1992 and 1995 to all Medicare-Medicaid-certified nursing homes in five states. After excluding patients with a history of mental disorders or retardation, we identified 23,073 patients age 65 years and over with a diagnosis of AD and 76,087 with VaD. We examined over 350 resident data items (demographic, diagnostic, clinical, treatment) collected with the federally mandated Minimum Data Set, drug data (brand name, dosage, route and frequency of administration for all drugs), and Medicare hospital claims. Cognitive status was measured with a 7-point cognitive performance scale. Estimates of drug use were adjusted for age, gender, race, and prevalence of respective disease. Patients with AD were younger and had more severe cognitive impairment than those with VaD. The latter had more comorbid clinical conditions (3.1 +/- 1.9 vs 2.3 +/- 1.7 for patients with AD) and received a greater number of total drugs (6.1 +/- 4.6 vs 5.3 +/- 4.3). Overall use of cardiovascular, anti-Parkinson, pulmonary, antineoplastic, and nutritional agents was less frequent among patients with AD than those with VaD. Results were consistent across different levels of cognitive impairment. Thus, patients with AD have fewer associated diseases and appear to be less intensively medically treated.