Disease Progression Independent of Relapse Activity vs. Relapse-Associated Worsening in Patients with Pediatric-Onset Multiple Sclerosis

Progression independent of relapse activity (PIRA) has been increasingly recognized in people with multiple sclerosis (MS; NEJM JW Neurol May 24 2022 and JAMA Neurol 2022; 79:682). To learn more about PIRA, investigators used data from the Italian MS Register on 16,130 patients with relapsing-remitting MS, including 1383 with pediatric-onset MS (POMS; median age at onset, 16), 14,113 with adult-onset MS (AOMS; median age at onset, 29), and 634 with late-onset MS (LOMS; median age at onset, 52).

Compared with patients with POMS, patients with LOMS had the highest incidence of PIRA (hazard ratio [HR], 2.98), followed by those with AOMS (HR, 1.42). Compared with the POMS patient group, the LOMS patient group had the lowest risk for relapse-asso…