Early Relapses May Not Correlate With the Onset of Secondary MS



For patients with multiple sclerosis (MS), the frequency of early inflammatory attacks may not be associated with the onset of secondary progressive MS, researchers wrote in the November 19 Archives of Neurology. In addition, relapse frequency may not be a valid surrogate marker for late disability.

Approximately 65% of patients with frequent early relapses converted to secondary progressive MS in a median of five years. These patients attained a Disability Status Scale (DSS) score of 6 in a median of seven years and a DSS score of 8 in a median of 17 years. The remaining patients with frequent early relapses did not convert to secondary progressive MS.

Antonio Scalfari, MD, at the Centre for Neuroscience of Imperial College London in the United Kingdom, and colleagues studied 730 patients with relapsing-remitting MS (RRMS). The study’s main outcome measure was the long-term evolution of the 158 patients who had three or more relapses during the first two years of their disease. In patients who converted to secondary progressive MS and participants grouped by number of early relapses, the investigators evaluated the predictive effect of time to secondary progressive MS on time to require a cane (ie, achieve DSS score of 6) and time to bedridden status (ie, achieve DSS score of 8).

Nearly 82% of patients with RRMS were women, compared with 63% of patients who converted to secondary progressive MS. Mean age at disease onset was 25.5 for patients with RRMS and 28.4 for patients who converted to secondary progressive MS.

Among patients who developed secondary progressive MS, longer latency to progression was associated with a lower probability of attaining DSS score of 6 and longer time to severe disability. The researchers observed the same association in patients matched by number of early attacks.

“We provide strong evidence that relapse frequency cannot be validated as a surrogate marker for late disability accumulation, questioning the current practice of using relapse rate as the primary end point in trials,” said Dr. Scalfari.

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