Abstracts

Rationale: Traditionally, for patients with partial onset seizures (POS) who fail initial antiepileptic drug (AED) monotherapy, physicians try sequential monotherapies (SM) before considering combination therapy (CT). However, relatively fewer of those patients (potentially refractory) achieve complete control with SM trials, which may have significant cost implications. This study compared seizure-related hospitalizations (SRH) and overall healthcare costs in POS patients receiving SM versus CT. Methods: POS patients (ICD-9 codes 345.4 and 345.5) during the calendar year 2009 were identified from the MarketScan Commercial and Medicare Database (32 million covered lives) and followed into 2010. 2008 data were used to ensure that patients had no previous epilepsy diagnoses or AED use. Patients were assigned to one of three treatment algorithms: SM, CT at onset (CT), and initial SM followed by CT (SMCT). Patients on SM received several single agents while patients on CT were treated with two or more agents within 29 days following initial AED prescription and maintained combination therapy for at least 60 days. Patients on only one AED or diagnosed with bipolar disorder, migraines or headache were excluded. SRH were limited to those with a primary or secondary diagnosis of POS. Costs were accrued for inpatient and outpatient services with a diagnosis of epilepsy and AED pharmacy costs. SRH and costs were adjusted for time on treatment. Mean and standard errors for average monthly costs were evaluated for total health care as well as by type of service. Results: 34,311 patients with newly diagnosed POS that received AEDs were initially identified. Patients receiving only one AED (n=20,035) were excluded, while patients receiving SM (n=3,112), CT (n=7,728), and SMCT (n=3,426) comprised the analysis population. Mean age was approximately 37 years with 45% male. At baseline, 6% of patients had diabetes, 13% hypertension, and 3% depression. There was no statistical difference in baseline demographics and comorbidities across treatment algorithms. The marginal cost per seizure-related hospitalization was $29,602 (STDERR: 271.78). Patients treated with SM had SRH of 0.055 per month compared to 0.028 (P<0.01) for patients treated with CT. Patients treated with SMCT had SRH of 0.085 and 0.001 per month during the pre- and post-combination period respectively. Mean total monthly reimbursed costs were $4,547 (202.56) for SM, $2,209 (201.02) for CT, and $3,464 (207.93) for those who received SMCT. Outpatient pharmacy consisted of $2,620 (93.84), $1,206 (59.74) and $2,340 (126.44) of total costs, respectively. Conclusions: Our study showed that for patients with potentially refractory epilepsy, combination therapy led to fewer seizure-related hospitalizations than sequential monotherapy, and consequently, lower overall healthcare costs. Therefore, early identification of these potentially refractory patients and appropriate AED management may help those patients achieve earlier and improved seizure control and also reduce healthcare costs for payers.