Abstracts

Rationale: In January 2008, the Food and Drug Administration (FDA) communicated concerns and later in May 2009, issued a warning about an increased risk of suicidality related to all antiepileptic drugs (AEDs)1,2. The purpose of this study was to evaluate the association between an FDA suicidality warning and AED prescription claims among Oklahoma Medicaid enrollees diagnosed with epilepsy and/or psychiatric disorder.Methods: A longitudinal interrupted time series design was utilized to evaluate Oklahoma Medicaid claims data from January 2006 through December 2009. A total of 9,289 continuously eligible individuals with a diagnosis of epilepsy and/or psychiatric disorder and at least one AED prescription claim were included. Trends, expressed as monthly change in logit of AED prescription claims, were compared among three time periods: a baseline period of 25 months (January 2006 to January 2008) before the FDA warning; the 16 months (February 2008 to May 2009) during the FDA warning (defined as between the initial FDA alert and the prior to the formal FDA warning label); and the 7 months (June 2009 to December 2009) after the FDA warning. Generalized estimation equations (GEE) were used to estimate trends in AED prescription claims while adjusting for covariates. Data management and analysis employed PC-SAS (v9.2), with the a-priori alpha set at 0.01.Results: A statistically significant increase in the trend of AED prescription claims was estimated at a rate of 0.01% per month (99% CI: 0.008% to 0.013%, p<0.0001) before the FDA warning period. However, no significant change in trend was detected during the FDA warning period (-20.0%, 99% CI: -70.0% to 30.0%, p=0.3472) and after the FDA warning period (80.0%, 99% CI: -20.0% to 200.0%, p=0.0323) when compared to pre warning period. After stratification by diagnosis, none of the diagnostic groups [patients with epilepsy alone (n=345), patients with epilepsy and comorbid psychiatric disorder (n=3,162), and patients with psychiatric disorder alone (n=5,782)] detected a significant change in trend during the entire study period (p>0.01).Conclusions: The FDA suicidality warning was not associated with a gradual reduction in overall AED prescription claims among this population. This suggests that there were no significant changes in AED prescribing during and after the FDA warning periods studied. References: 1. U.S. Food and Drug Administration. Information for healthcare professionals: Suicidal behavior and ideation and antiepileptic drugs. http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm100192.htm. Accessed May 1, 2013. 2. U.S. Food and Drug Administration. Antiepileptic drugs. May 5, 2009; http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm074939.htm. Accessed May 1, 2013.