Abstracts

RATIONALE: The purpose of this study was to describe the use of antiepileptic drugs (AED) by elderly people upon entry into nursing homes, and to compare residents with and without AED use at admission. METHODS: All admissions aged 65 and older from January-March 1999, to all nursing homes (N=510) owned by Beverly Enterprises, Inc., located in 31 states were included in the study (N=10,318). Data were the Minimum Data Set (MDS) at admission and all medication orders. Analysis was logistic regression with AED use as the dependent variable. The covariates were demographic, diagnostic, clinical and geographic variables. RESULTS: Overall AED use at entry into nursing home was 10.3% 95% CI: 9.7-10.9). AEDs most frequently used were lorazepam (3.4%), phenytoin (2.0%), valproic acid (1.4%) and gabapentin (1.2%). The most important factor associated with AED use upon entry was a diagnosis of epilepsy/seizure disorder (odds ratio (OR)=15.0; 95% CI: 12.3-18.4). AED use was also statistically significantly (p < 0.05) related to bipolar disease (OR=8.1), anxiety disorder (OR=4.9), peripheral vascular disease (OR=2.0), age groups (65-74 years OR=1.00; 75-84 years OR=1.7; 85+ years OR=1.3), region (Northeast OR=1.0; South OR=1.5; Midwest OR=1.8; West OR=1.4), a low cognitive performance score (OR=1.2), dementia (OR=1.2), depression (OR=1.4) and hip fracture (OR=0.3). Admissions with AED use were statistically significantly affected by interaction terms: peripheral vascular disease and hip fracture (OR=3.3), activities of daily living (ADL) and hip fracture (OR=1.1), low cognitive performance score and ADL (OR=0.99), peripheral vascular disease and ADL (OR=0.95), anxiety disorder and depression (OR=0.6), congestive heart failure and peripheral vascular disease (OR=0.5), hip fracture and dementia (OR=0.4), bipolar and schizophrenia (OR=0.2), and epilepsy and anxiety (OR=0.2). CONCLUSIONS: Our finding that 1 in 10 elderly admissions take an AED in a nationwide sample of over 500 nursing homes is surprising. Other unexpected results included geographic and age differences that suggest need for further research on prescribing practices. Study supported by NINDS P50-NS16308.