Clinical and economic burden of breakthrough seizures

Abstract

Purpose: The purpose of this study was to measure health-care resource utilization and costs in treatment-adherent, previously seizure-free patients with epilepsy who were treated in the inpatient/emergency room (ER) setting for new-onset seizures, compared with matched controls.

Methods: The study used a retrospective case/control study design using administrative claims from the IMS PharMetrics™ database. We identified adult patients with epilepsy with 1+ ER visit/hospitalization with primary diagnosis of epilepsy between 1/1/2006 and 3/31/2011, preceded by 6months of seizure-free activity and antiepileptic drug (AED) treatment adherence (≥80% of days covered by any AED); the first observed seizure defined the "breakthrough" seizure/index event. Treatment-adherent patients with epilepsy without any ER/hospital admission for seizures served as controls: an outpatient epilepsy-related medical claim within the selection window was chosen at random as the index date. The following were continuous enrollment requirements for all patients: ≥12-month pre- and ≥6-month postindex. Each case matched 1:1 to a control using propensity score matching. All-cause and epilepsy-related (epilepsy/convulsion diagnosis, AED pharmacy) resource utilization and unadjusted and adjusted direct health-care costs (per person, 2012 US dollars (USD)) were assessed in a 6-month follow-up period.

Principal results: There were 5729 cases and 14,437 controls eligible. The final sample comprised 5279 matched case/control pairs. In unadjusted analyses, matched cases had significantly higher rates of all-cause hospitalization and ER visits compared to controls and significantly higher total all-cause direct health-care costs (median $12,714 vs. $5095, p<0.001) and total epilepsy-related costs among cases vs. controls (median $7293 vs. $1712, p<0.001), driven by higher inpatient costs. Among cases, costs increased with each subsequent seizure (driven by inpatient costs). Cases had 2.3 times higher adjusted all-cause costs and 8.1 times higher adjusted epilepsy-related costs than controls (both p<0.001).

Conclusion: Inpatient/ER-treated breakthrough seizures occurred among 28.4% of our treatment-adherent study sample and were associated with significant incremental health-care utilization and costs, primarily driven by hospitalizations. Our findings suggest the need for better seizure control via optimal patient management and the use of effective AED therapy, which can potentially lower health-care costs.

Keywords: Breakthrough seizures; Cost; Epilepsy; Resource utilization; Seizure control.