Abstracts

A number of new anti-epileptic drugs (AED) having characteristics favorable for use in the elderly have been introduced over the past decade. While empirical evidence and clinical practice identify phenobarbital (PHB) and phenytoin (PHT) as having more serious adverse effect profiles, especially for the elderly, only recently has an expert consensus guideline advocated use of lamotrigine, carbamazepine, and gabapentin as first-line and phenobarbital and phenytoin as second-line AED for the elderly. Yet, early analyses for this project suggest that clinical practice is quite inconsistent with these recommendations. The aim of this study was to determine which newly diagnosed geriatric patients receive PHB and PHT in a population of elderly patients for whom cost does not impact the type of drug prescribed.
National inpatient, outpatient, and pharmacy data from the Veterans Health Administration (VA), were used to identify veterans [ge] 65 years with an epilepsy diagnosis during 2000 who also received antiepileptic drugs from the VA in 2000. Patients who were seen in the VA during 1997-2000 with no previous diagnosis of epilepsy were identified as newly diagnosed and selected for this study. We classified patients[rsquo] antiepileptic drug regimen based on the AED they received that year. We identified demographic characteristics (age, sex, race), neurology consultations, disease severity and comorbidities using inpatient and outpatient data. Disease severity was defined as a dichotomous measure that identified those requiring emergency or hospital care for epilepsy, fosphenytoin or diazepam IV, and those coded as having intractable epilepsy as having more severe disease (0,1). Comorbidities were a count of 36 physical and 6 psychiatric disorders as described by Selim.
About 10% received phenobarbital regimens, 65% received phenytoin regimens, and 25% received regimens with only recommended AED. Logistic regression analyses indicated that those with more severe epilepsy were less than half as likely to receive PHB monotherapy than other monotherapies (OR: 0.49, 95% CI 0.23-0.99) and PHB combinations than other combinations (OR: 0.33, 95% CI 0.15-0.73). Patients receiving neurology consultation were less likely to receive PHT monotherapy than recommended monotherapies (OR: 0.49, 95% CI 0.39-0.61). Whites were less likely to receive PHT monotherapy than recommended monotherapy (OR: .59, 95% CI .45-.76).
Despite empirical evidence, most older veterans newly diagnosed with epilepsy received PHB and PHT. Disease severity was important for PHB and processes of care predicted receipt of PHT. It is important to further explicate how processes of care contribute to treatment patterns. However, assessment of the AED effectiveness in clinical practice is critical to provide clinicians with more evidence on which to base prescribing decisions.
[Supported by: VA HSR[amp]D Postdoctoral Fellowship]