Risk factors for convertion to clinically defined multiple sclerosis after clinically isolated syndrome in a racially mixed Brazilian cohort

•Risk factors for conversion in Whites were also found in this racially-mixed cohort.•Shortest time for conversion for CDMS was related to initial cerebellar and sphincter impairment.•3-Patients treated earlier with DMD took longer to convert to CDMS.•Ancestry had no effect on the time until conversion.•Filling the MRI criteria for MS increased the annual likelihood of conversion to CDMS.

Clinically isolated syndrome may reflect the first symptom of Multiple Sclerosis. Though more prevalent in Caucasians, MS can also affect Afrodescendts. Modifying disease drugs can delay convertion to clinically defined multiple sclerosis, therefore, identify patients at a higher risk of convertion is important. However data of risk factors in racially mixed population are scarce.ObjectivesTo analyze predictor factors to the conversion from CIS to CDMS in a mixed race Brazilian cohort.Patients and methodsIt is a prognostic observational retrospective study, in 122 patients from MS referential center at Hospital da Lagoa, Rio de Janeiro-Brazil. Demographic and clinical features, as well as MRI and cerebrospinal fluid data were analyzed.ResultsAfter five years follow-up 87.3% converted to CDMS. Regarding to median time of conversion, there was no difference between gender, race, age at onset, mono or polysymptomatic presentation. Cerebellar CIS significantly reduced time to second event; likewise sphincter impairment. Considering DMD, patients without treatment converted earlier.ConclusionAncestry did not influence conversion risk. Cerebellar and shpincter impairment as well as MRI criteria both Barkhof/Tintoré and Swanton were important predictors. In future studies it should be also analysed the risk factors of progression in mixed race populations.