Abstracts

Rationale: Momentous advances in treatment of Multiple sclerosis (MS) have greatly increased the quality of life and life expectancy of MS patients. We hypothesized that this trend towards improved disease control would be paralleled by a decrease in incidence of epilepsy in MS. We thus aimed to investigate the occurrence and risk of epilepsy in different time periods of MS diagnosis, as surrogates for introduction of different generations of immunomodulatory therapies. Methods: We carried out a retrospective cohort study including 10779 patients from the Swedish MS register with MS diagnosis between the years 1992 - 2014. Data on epilepsy diagnosis was extracted from the validated national patient register. Based on the year of MS diagnosis, patients were divided into five, five-year wide diagnosis groups between 1992 – 2014. We estimated the incidence rate and 10-year risks of epilepsy for these cohorts, the latter using Kaplan-Meir survival analysis. Results: The incidence rates of epilepsy showed a decreasing trend the more recent the year of diagnosis (Figure 1). The 10-year risks of epilepsy also showed a decreasing trend, however, there was some overlap in the confidence intervals (Figure 2). Conclusions: Our preliminary results show a decreasing trend in incidence and risk of epilepsy the more recent the year of MS diagnosis. The differences were however not significant and further analysis is needed to determine if there exists a true decline. Funding: Swedish society of medicine, Göteborgs läkaresällskap, Swedish Society for Medical Research, Magnus Bergvall Foundation, Jeansson Foundation, Felix Neubergh foundation.