Progression Independent of Relapse Activity in Early Multiple Sclerosis

Progression independent of relapse activity (PIRA) is increasingly recognized as an indicator of disease progression in patients with relapsing multiple sclerosis (NEJM JW Neurol 2022 Mar 1 and Brain 2022; 145:3147). In this retrospective, single-center analysis, 1128 patents with a first demyelinating event were followed for up to 7 years to assess the effects of PIRA on disability progression.

PIRA was observed in 25% of patients, of whom 31% had PIRA within 5 years of diagnosis with multiple sclerosis. Of 277 patients with PIRA and MRI scans, 51% developed PIRA associated with new MRI activity. Patients with PIRA were older, had more T2 brain lesions, and more often had oligoclonal bands in CSF. Patients with PIRA had a 0.18-point annual …