Predictors and Conversion Rate of Clinically Isolated Syndrome To Clinically Definite Multiple Sclerosis: A Follow-Up Study in Patients Living in the Southern Part of Iran

Background: clinical course of clinically isolated syndrome (cis) is variable, and identifying patients who will eventually develop multiple sclerosis (ms) is essential. objectives: to assess the conversion rate of cis to clinically definite multiple sclerosis (cdms) and its predictors in southern iran. materials & methods: a total of 143 cis patients registered to fars multiple sclerosis society (fmss) were enrolled in the study from 2006 until 2012, and all of them were followed for 5 years. also, their demographic and mri data were recorded. the obtained data were analyzed by univariate and multivariable cox regression models in spss v. 17. p<0.05 was considered statistically significant. results: about 26.6% of patients progressed to ms after a mean duration of 3.4±1.1 years. the conversion rate was 27.6% in patients presented with optic neuritis, and 25.6% in patients presented with spinal cord problems. although it was not statistically significant (p=0.23), the mean age of the patients who converted to ms was lower at the onset of the presentation (27.6 vs. 29.4 years). in patients who had 3 or more mri lesions, the conversion rate was 49.2%; however, it was only 9.8% in subjects who had fewer than 3 lesions (or=8.95, 95% ci=3.69–21.7, p <0.001). women had higher conversion rate though it was not statistically significant (or=2.09, 95% ci=0.57–7.64, p=0.26). conclusion: our results supported this supposition that the number of mri lesions at baseline can be used as a predictor of cis conversion to ms.