Abstracts

Rationale: Epilepsy affects up to 90% of patients with TSC compared to a prevalence of 0.5-1% in the general UK population. Epilepsy in patients with TSC is characterized by early onset, high severity, and resistance to traditional antiepileptic medications. As a consequence, the clinical burden associated with epilepsy in TSC is thought to be high. This study examines epilepsy, treatment approaches and associated outcomes in the UK. Methods: TSC patients in the Clinical Practice Research Datalink (CPRD) and linked Hospital Episodes Statistics (HES) database were retrospectively identified between 1997 and 2012. The CPRD is a database that includes ~680 general practices and history from ~15 million patients. Epilepsy and associated healthcare services were determined via review of diagnostic codes, procedure codes and prescribed antiepileptic therapies. Results: 341 patients with a diagnosis of TSC were identified, 71% (N=241; 52% male) of whom had a record of epilepsy. In patients with epilepsy with data from birth (N=59), median age at the first record related to epilepsy was 0.8 years (interquartile range: 0.4-1.2); 71% of patients had their first record at <1 year of age. The most common antiepileptic medications prescribed in the treated population (N=200) were carbamazepine (56%), sodium valproate (46%), and lamotrigine (34%); one in four patients (26%) were prescribed vigabatrin during their history. Approximately one in five (19%) treated patients were managed with a combination of 3 or more antiepileptic medications suggesting difficult to control epilepsy. Only 24% of epileptic patients had a record of being seizure free for 12 months. Of patients with epilepsy where data was available from childhood into adulthood (N=69), 83% still had continuing seizures in adulthood. On average, outpatient visits to a neurologist or pediatrician occurred more frequently in pediatric epileptic patients (2.8 visits per person-year [min. 0.1; max. 13.4]) vs. adult patients (0.7 visits per person year [0.1; 7.3]). Over half of epileptic patients (57%) had at least one hospitalization due to epilepsy (min. 0.1; max. 2.4 admissions per person-year); 73% of hospitalizations presented via the emergency room. Conclusions: This study is unique in that it presents the real world burden of epilepsy in TSC by examining a community sample of patients with TSC; the majority of published studies focus on specialist hospital outpatient clinics. It confirms high prevalence and early onset of epilepsy in TSC, implying significant burden. Multiple treatment regimens, frequently using combinations of antiepileptic medications, suggest more severe forms of epilepsy that are complicated to manage. This study attempts to identify the factors associated with epilepsy in TSC that lead to poor patient outcomes.