Cross-prevalence of multiple sclerosis and stroke evaluated on cohorts of four independent specialty medical centers

Background: Numerous sources reported the increased risk of cerebrovascular accidents (CVA) in individuals with multiple sclerosis (MS), without a single study thus far challenging the conclusion. Before addressing hypothesis on potential cause-effect relationships, a question whether there are indeed frequent comorbidities between MS and CVA needed to be answered.

Methods: Authors designed a study to evaluate substantial populations of four independent neurology centers with the purpose to assess the prevalence of CVA diagnosis in patients with MS, and vice versa. Data of subjects meeting enrollment criteria were entered into a single database. Authors compared obtained data with the MS and CVA prevalences in the populations of specific countries.

Results: Of the 1881 subjects' records, the main diagnosis was MS for 51.5% and CVA for 48.5%. The CVA prevalence as a secondary diagnosis among MS subjects was 1.47% in USA cohort and 1.65% in combined USA+ Russian Federation (RF) cohorts, which is lower than known prevalence of stroke in adult population of these regions. The prevalence of MS as a secondary diagnosis among subjects with stroke in USA cohort was 0.4% and in combined USA+RF cohorts was 0.33%, which is higher, but not statistically different from calculated MS prevalence in both USA and RF populations combined.

Conclusion: Thus, authors found that prevalence of CVA in cohorts with MS of 2 independent centers was at least not higher, than that in general population, which differs from previously published data.