Abstracts

Rationale: Lennox–Gastaut syndrome (LGS) is often thought of as a pediatric disorder; however, its symptoms and impairments evolve into adulthood, and under-recognition of LGS in adults may lead to suboptimal management. Current understanding of LGS, its treatment patterns and cost burden over the course of patients’ (pts) lives is limited. This study aimed to quantify the clinical and economic burden of LGS from pediatric to adult years.Methods: Health insurance claims for epilepsy pts (≥2 claims for ICD-9 345.xx) of all ages were obtained from 6 state Medicaid programs. LGS pts were identified using a claims-based classifier developed using a random forest methodology, and observed from 1st diagnosis of epilepsy to death, or end of data availability/study eligibility. Pts were categorized into yearly age cohorts based on their observation period; some pts contributed to ≥1 age cohort. Rates of etiologies, comorbid conditions, and medication use were assessed using proportions. Mean healthcare costs were assessed by type of service. All outcomes were plotted against time-series panels to depict changes over time.Results: The number and proportion of epilepsy pts with LGS increased from early age to about age 10 and then declined gradually over time (range: 1.0%–8.4%; Figure 1). The 3 most common etiologies in LGS pts were brain malformations, encephalopathy, and West syndrome, which all peaked in childhood. As for comorbid conditions, the rate of delayed development reached 79.6% before age 5, and declined drastically after age 20. In contrast, the rate of intellectual developmental disorder (mental retardation in ICD-9) slowly increased to 44.5% then stabilized. The majority of LGS pts had ≥1 antiepileptic drug (AED) (range: 62.6%–82.3%). Broad-spectrum AEDs contributed to the majority of these prescriptions, while 28.4%–54.2% LGS pts had narrow-spectrum AEDs. Use of AEDs indicated only for LGS (i.e., clobazam and rufinamide) was not common in LGS pts. The greatest use of both agents peaked at ages 0–5 (maximum rate: 17.5% [clobazam], 7.4% [rufinamide]), and declined substantially to about 5.5% at age 18, and <1.0% at age 60. Mean total healthcare costs among LGS pts were consistent over time (range: $32,460–$49,078 per patient per year [PPPY]). Of all healthcare costs, medical costs were the main cost drivers (range: $28,830–$44,435 PPPY), and pharmacy costs made up only a small portion (range: $1,704–$5,672 PPPY). Compared to all epilepsy pts, LGS pts had substantially higher total healthcare costs (range, all epilepsy pts: $9,273–$28,798 PPPY) (Figure 2). The largest component of medical costs in LGS pts was home-based care in early years and long-term care after middle age.Conclusions: LGS has a lifelong impact on pts, yet LGS may be underdiagnosed in adults. Additionally, while AEDs are prescribed to LGS pts, it seems that LGS-specific AEDs are underutilized. Increased clinical attention to LGS beyond pediatric years is warranted. Future studies should further assess the clinical and economic burden of LGS in adult pts. Funded by Lundbeck LLC