Abstract

Background: Iran, as a middle income country, is one of the places with high and rising prevalence of multiple sclerosis (MS). Regarding the substantial economic burden, reviewing the trend in prescribed disease modifying treatments (DMTs) could be of help. Here we studied the DMT information of nearly 14000 MS cases and its trends change for 30 years to improve health services to patients.Methods: The population base of this descriptive-analytical (cross-sectional) study consisted of all MS patients in the nationwide MS registry of Iran (NMSRI), up to August 1, 2021. Registrars from 15 provinces, 24 cities, 13 hospitals,8 MS associations, 16 private offices, and 7 clinics had entered the data.Results: Overall, 14316 cases were enrolled. The majority (76.1) were female. The youngest and eldest patients were 5 and 78 years old, respectively. Diagnosis delay was under one year in most cases (median: 0, IQR: 0 - 1). Most (61.4) had RRMS. Generally, platform injectables (IFN beta, glatiramer acetate) were the most used DMTs until 2010. It seems that introduction of newer agents (antiCD20s and oral DMTs) resulted in a decrease in the use of former drugs since around 2015. Some unusual practices are prominent such as using not approved DMTs for PPMS over the years, or administering high efficacy drugs like natalizumab for CIS. The results indicate the remaining popularity of first line injectable DMTs in female and pediatric patients.Discussion: Mean age (SD) at onset in our study (29 +/- 8.8) is near the statistics in Asia and Oceania (28 +/- 0.7). Concerns about COVID-19 had a noticeable impact on administering high efficacy drugs like rituximab and