Prevalence of Progression Independent of Relapse Activity and Relapse-Associated Worsening in Patients With AQP4-IgG–Positive NMOSD
Pakeeran Siriratnam, Saif Huda, Anneke van der Walt, Paul G. Sanfilippo, Sifat Sharmin, Yi Chao Foong, Wei Zhen Yeh, Chao Zhu, Samia J. Khoury, Tünde Csépány, Barbara Willekens, Masoud Etemadifar, Serkan Özakbaş, Petra Nytrová, Ayşe Altıntaş, Abdullah Al‐Asmi, Cristina Ramo‐Tello, Guy Laureys, Francesco Patti, Dana Horáková, Matteo Foschi, Cavit Boz, Pamela McCombe, Recai Türkoğlu, Jeannette Lechner‐Scott, Izanne Roos, Tomáš Kalinčík, Vilija Jokubaitis, Helmut Butzkueven, Mastura Monif, for MSBase
Abstract
OBJECTIVES: In aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-IgG NMOSD), disability accrual is mostly attributed to relapses. This study aimed to assess the prevalence of progression independent of relapse activity (PIRA) and relapse-associated worsening (RAW) in AQP4-IgG NMOSD. METHODS: This was a retrospective cohort study of patients with AQP4-IgG NMOSD enrolled in the MSBase international data registry. Patients required a minimum of 3 recorded Expanded Disability Status Scale (EDSS) scores: baseline, event, and a 6-month confirmation score. Presence and absence of relapses between the baseline and event EDSS scores determined RAW and PIRA, respectively. Descriptive statistics were used to present the results. RESULTS: A total of 181 patients followed for a median of 4.5 years (Q1 1.7, Q3 7.8) were included. Most patients were female (88.4%), and the median age at disease onset was 38.1 years. Overall, 4 patients (2.2%) developed 5 incidences of PIRA and 13 patients developed RAW (7.2%). DISCUSSION: This multicenter study highlights that PIRA is very rare in AQP4-IgG NMOSD. Limitations of this study include the sole focus of overall EDSS to measure disability, lack of requirement for a second EDSS score to confirm baseline EDSS, and the absence of magnetic resonance imaging information for all patients.