Background: There is growing consensus that neurologists should consider disease-modifying therapies early in multiple sclerosis (MS). However, there is a subgroup with a natural benign course, in which treatment could be postponed. We sought to determine the frequency of benign MS and early clinical factors that may predict a benign course.
Methods: We performed a systematic review of the existing literature on benign MS, which was defined as minimal or no disability equivalent to a score on the Expanded Disability Status Scale (EDSS) < or = 3.0 at least 10 years after disease onset
Results: Only a small number of studies of adequate quality was available. In total there were nine published studies representing 2,204 patients. The estimated frequency of benign MS was 26.7%. Onset with optic neuritis, onset before the age of 40 years, absence of pyramidal signs at presentation, duration of first remission more than 1 year, and only one exacerbation in the first 5 years after onset of MS, were associated with a benign course.
Conclusions: From the existing literature a set of unrelated clinical characteristics emerged that was associated with a benign course of MS. However, there is a need for prospective studies to define more precisely clinical and paraclinical predictors of benign MS.