Multiple Sclerosis and Progression Independent of Relapse Activity

In patients with multiple sclerosis (MS), progression independent of relapse activity (PIRA) is increasingly appreciated to occur even in early relapsing patients (NEJM JW Neurol Jan 2021 and JAMA Neurol 2020; 77:1132). Now, researchers have assessed whether PIRA was associated with accelerated brain loss in the Swiss MS Cohort study, which included 516 patients with relapsing MS and 1904 MRI scans, with median follow-up of 3.2 mean years.

PIRA-only events occurred in 46 patients. Compared with 334 stable patients, those with PIRA had accelerated volume loss of whole brain, total gray matter, and cortical gray matter, along with more cortical thinning. Compared with 122 patients with relapse activity, no differences were detected in those wi…