Abstract| Volume 37, 101553, January 2020

Incidence and Prevalence of Multiple Sclerosis in the Sultanate of Oman: A Hospital Based Study

      The prevalence of multiple sclerosis (MS) is changing globally. In this study, we aim to estimate the incidence and prevalence of MS in Oman over the period from 2006-2019.
      This is a retrospective observational hospital-based study. Omani patients with Multiple Sclerosis (MS) are fWe recruited MS patients from the two major referral Neurology centres in Oman viz. Sultan Qaboos University Hospital and Khoula Hospital for this observational study. All Omani adult patients who were diagnosed with MS based on the revised McDonald criteria over the period from January 2006 to May 2019 were included. The total population of Oman as of June 2019 was obtained from the national census data. We retrieved the following data from the electronic case records: age at disease onset, gender and the year of diagnosis.
      Based on the national census data, the total Omani population was 2,652,199 (as of June 2019). Four hundred and twenty-two (422) patients were diagnosed with MS during the study period. The estimated crude prevalence was 15.9 per 100000, with a female to male ratio of 2.2:1 and with the initial MS symptoms occurring at a mean age of 27.3 years (S.D: 7.7 years; range: 9-59 years). Eighty three percent of the patients had the disease onset between the age of 19-40 years and 9% had the initial manifestation at less than 19 years of age. The annual incidence had increased from 1.00 case per 100000 in 2015 to 1.37 cases per 100000 in 2018.
      MS prevalence in Omani population has increased from 4 per 100000 in 2000 (based on the previously published hospital-based study from Oman) to 15.9 per 100000 in the current study. Oman should be considered as medium risk zone for MS. It is to be noted that the MS prevalence in Oman is the lowest among the Arabian Gulf countries. The increase in MS annual incidence rate in Oman is similar to what has been observed globally. Further studies are needed to assess the specific risks for MS in our population.