All MS patients originally from MENA countries(MENA-MS) were identified through the MS Clinic Registry of St. Michael’s Hospital in Toronto, Canada, which captures information on all clinic patients. Age and sex-matched MS patients of European descent(EUR-MS) were also identified. Sequential brain and cervical spine MRIs were reviewed for radiological activity. Disability progression was assessed by change in Expanded Disability Status Scale(EDSS) between first and last clinic visits and the Progression Index(PI).Overall disease severity was assessed by the MS Severity Score(MSSS). Student’s t-test and multivariable linear regression evaluated relationships between groups. 

192 MENA-MS and 192 EUR-MS patients were included. The mean age in both groups was 42.9 years and 67% were female. 25% and 24% of EUR-MS and MENA-MS had progressive disease, with mean disease duration of 11.5 and 11.43 years, respectively. Measures of clinical and radiological disease activity, including annualized relapse rate, baseline EDSS, and annual MRI disease activity did not differ. Disability progression was higher in MENA-MS (EDSS change=0.24 vs. 0.06,p=0.01) and MENA-MS showed greater disease severity with respect to MSSS(3.12 vs. 2.67,p=0.04) and PI(0.34 vs. 0.27,p=0.07).