Rarity of silent progression: PIRA and RAW in myelin oligodendrocyte glycoprotein antibody–associated disease

In myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), disability is typically attack-related and frequently remain stable over time if no relapses occur. This retrospective cohort study assessed the prevalence of progression independent of relapse activity (PIRA) and relapse-associated worsening (RAW) in Korean patients with MOGAD from five referral centers. Among 205 patients, 116 with ⩾1 year of follow-up and a minimum of 3 documented EDSS scores were eligible for inclusion. Over a mean follow-up of 62.2 months, PIRA occurred in two patients (1.7%) and RAW in six patients (5.2%), highlighting that PIRA is a rare and atypical event in MOGAD.