Comparison of Drug Utilization Patterns in Observational Data: Antiepileptic Drugs in Pediatric Patients

Physicians require information on the comparative benefits and harms of medications for optimal treatment decisions. However, this type of data is limited, especially for pediatric patients.

Our aim was to use observational data to measure and compare medication utilization patterns in a pediatric patient population.

Using pharmacy claims data from a large, national-scale insurance program in the USA, we identified all patients with a diagnosis of epilepsy treated with a first-generation antiepileptic drug (carbamazepine, ethosuximide, phenobarbital, phenytoin, or valproate) or a second-generation antiepileptic drug [carbamazepine extended release (XR), gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, valproate XR, or zonisamide]. Treatment periods were defined on the basis of prescription fill dates and medication days supplied. Medication use was measured for individual antiepileptic drugs and for first-generation and second-generation drugs as groups.

There were 2527 patients (54 %) who initiated therapy with first-generation antiepileptics and 2139 patients (46 %) who initiated therapy with second-generation antiepileptics. First- and second-generation drugs had the same 1-year retention rates [26 % (95 % confidence interval (CI) 24-28) and 26 % (95 % CI 25-28), respectively], and 26 % of patients (95 % CI 25-28) and 29 % of patients (95 % CI 27-31) who started on a first- or second-generation antiepileptic medication, respectively, resumed treatment with the initial drug after discontinuation. Overall, 73 % of patients (95 % CI 71-74) were treated with only one antiepileptic drug, with similar rates for patients started on first- and second-generation drugs [71 % (95 % CI 69-73) versus 74 % (95 % CI 72-76)].

Comparing drug utilization patterns in a pediatric population using observational data, we found similar rates of retention and therapeutic changes. These findings are consistent with the available comparative data and demonstrate an approach that could be extended to other drug classes and conditions in pediatric populations to examine drug effectiveness.