A descriptive analysis of drug treatment patterns and burden of illness for pediatric patients diagnosed with partial-onset seizures in the USA

Mallik Angalakuditi¹, Nupur Angalakuditi^2
1Georgia State University, Robinson School of Business, Atlanta, GA, ²New York Medical College, Valhalla, NY, USA

Purpose: The objective of this retrospective claims study was to describe antiepileptic drug (AED) treatment patterns and burden of illness in children with epilepsy.
Methods: Data were administrative claims from a US commercial health plan. Patients were between 2 and 17 years of age and had one or more pharmacy claims for an oral AED from July 1, 2005, to November 30, 2009. The index date was defined as the first AED claim. Patients had one or more medical claims for epilepsy (ICD-9-CM 345.xx) during the 6-month pre-index period and were continuously enrolled for 12 months post index. Of the 17 AED medications used to identify patients, eleven medication cohorts had more than 100 patients: (1) carbamazepine (CAR); (2) clonazepam; (3) gabapentin (GAB); (4) lamotrigine (LAM); (5) levetiracetam (LEV); (6) oxcarbazepine (OXC); (7) phenobarbital; (8) phenytoin (PHY); (9) topiramate (TOP); (10) valproate (VAL); and (11) zonisamide (ZON).
Results: There were 3889 children who met the inclusion criteria. There were some differences in patients across the eleven AED treatment cohorts based on index therapy in age, gender, geographic location, Charlson comorbidity score, AHRQ comorbid conditions, as well as epilepsy-related risk factors and comorbidities. Of the 17 AEDs examined, the most frequently prescribed were OXC (21%) and LEV (19%); the least prescribed AED was GAB (1%). Their respective mean post-index pharmacy and total costs were as follows: OXC, US$2095 and US$5556; LEV, US$3025 and US$9121; and GAB, US$917 and US$1597. The overall post-index mean pharmacy costs were US$2637, and mean total costs were US$6813.
Conclusion: Study results demonstrate differences in patient demographic and clinical characteristics across AED medication cohorts. Some cohorts have greater odds of a switch, or augmentation than the reference comparator CAR cohort. Variation was also observed in brand or generic medication use. LAM and TOP had the highest annual pharmacy costs of all the drugs.

Keywords: epilepsy, epidemiology, antiepileptic drugs, partial-onset seizure, pediatrics