Abstracts

The incidence of epilepsy is most common in the elderly, and treatment choices may be complicated by physical and psychiatric comorbidities. Studies have not systematically examined the patterns of comorbidities in older patients with new onset epilepsy., We identified new onset epilepsy patients using national diagnostic and administrative data from the Veterans Health Administration and Medicare data files and national VA pharmacy data. We first identified individuals who were 65 years or older in each year (2000-2004). Individuals with a first diagnosis (ICD-9 codes) of epilepsy (345) or convulsion (780.39) with a concomitant first prescription for an antiepileptic drug (AED) were classified as having new onset epilepsy. Of those older veterans with both a diagnosis of epilepsy and a concomitant AED (N=69,494), 9,234 met the criteria for new onset epilepsy. We then identified the common comorbid conditions that may affect treatment patterns., The cohort of new onset epilepsy patients was primarily male (98%), White (78%; 16% Black, 5% Hispanic) with a mean age of 75.1 years. On average, these individuals had 11 physical comorbidities and slightly less than one psychiatric comorbidity. Approximately 30% had a prior stroke and 16% had a history of transient ischemic attacks. This group was also substantially affected by metabolic syndrome: 92% hypertension, 52% type 2 diabetes, and 68% hypercholesterolemia. Psychiatric comorbidities included depression (22%), psychosis (18%) and anxiety (13%). On average these patients received 17 (SD=8.8) unique classes of drugs in addition to their AEDs, including many that pose potential interactions with older AEDs (e.g. warfarin, statins)., The comorbidity profile of this populations indicates that they have profound comorbid disease. Diseases such as hypercholesterolemia and coagulopathy are commonly treated with drugs that have been found interact with older enzyme inducing AEDs. We know that over 80% of these patients received these older, enzyme inducing AEDs (65% phenytoin; 5% phenobarbital, 10% carbamazepine) Further research is needed to determine the extent to which drug-drug interactions occurred, and the impact of these interactions. It is possible that treatment with older, less expensive AEDs is offset by hidden costs that occur as a result of drug-drug interactions (e.g. higher mortality due to subsequent stroke or MI for patients treated with statins and who receive little benefit due to the drug-drug interaction) or hip fractures that may occur due to osteoporosis that has been associated with chronic use of enzyme inducing AEDs. Much research is needed to explore these hypotheses., (Supported by Department of Veterans Affairs, Health Services Research and Development Service.)