Abstracts

Rationale: Several studies have demonstrated an increased overall prevalence of epilepsy in multiple sclerosis (MS) populations, but estimates have varied widely. Most previous studies have been based either on incidence cohorts recruited prior to modern MS therapy or single-centre evaluations of medical records. We aimed to determine the prevalence of epilepsy in a population-based manner. Methods: The Swedish Multiple Sclerosis registry contains data on >15.000 individuals with MS and has a coverage of approximately 80% of Swedish patients with MS. By using Swedish personal identification numbers, the MS registry was cross-linked to the Swedish national patient registry, containing diagnosis from all inpatient care since 1987 and some hospital-based outpatient care since 2001. Results: An epilepsy diagnosis was detected in 3.5 % of individuals with MS, compared to approximately 1.4% in a control population selected from the Swedish comprehensive population registry with two randomly selected individuals matched for age at onset of MS and gender for each MS patient. Conclusions: These preliminary results from comprehensive national registries suggest an increased cumulative incidence of epilepsy in MS. Analyses are on-going regarding prevalence of epilepsy in Swedish MS patients over time, associations between epilepsy and mortality, and associations between epilepsy and MS characteristics such as disability, disease-modifying therapy, and duration. Funding: The Swedish Society of medicine, Jeanssen Foundation