Therapeutic Plasma Exchange in Neuromyelitis Optica Spectrum Disorders and Related Disorders in Resource‐Limited Settings: Outcomes in a Multiethnic Single‐Center Population

Abstract

We evaluated therapeutic plasma exchange (TPE) efficiency in treatment of a single relapse in steroid‐refractory patients with neuromyelitis optica spectrum disorders (NMOSD) in a multi‐ethnic resource‐limited setting. This was a historical cohort study on the clinical outcomes post‐TPE in a multiethnic cohort of 53 steroid‐refractory NMOSD patients at a single Malaysian tertiary center. Primary outcomes, assessed both pre‐ and post‐TPE, were Medical Research Council scale of muscle power, Modified Rankin Scale, Expanded Disability Status Scale (EDSS), and visual acuity. Secondary outcomes were ambulatory status and target neurological deficit (TND)‐based TPE response. Significant improvements in Medical Research Council, Modified Rankin Scale, EDSS, and visual acuity (P <\u20090.001) were observed at 1‐month post‐TPE with further improvement of EDSS at 6\u2009months (EDSSΔ6) post‐TPE (P <\u20090.001). At 6\u2009months post‐TPE, 87% of patients has successful TND‐based TPE response and 69.8% were ambulating without support. Patients with anti‐aquaporin 4 seronegativity (P =\u20090.004), myelitis and brainstem features at first relapse (P =\u20090.004), longer cord lesions (P =\u20090.030), higher pre‐TPE EDSS of ≥8 (P =\u20090.018) and delayed TPE initiation of >14\u2009days (P =\u20090.047) were significantly associated with improved EDSSΔ6. TND‐based TPE response was significant in absence of cord atrophy (P =\u20090.030). TPE is an effective treatment for steroid‐refractory acute relapses of NMOSD in a multiethnic Malaysian population despite its resource‐limited setting. The predictive factors of EDSSΔ6 improvement were anti‐aquaporin 4 seronegativity, longer cord lesions, and higher pre‐TPE EDSS. Absence of cord atrophy was predictive of better TND‐based TPE response. Unexpectedly, our study showed that delayed TPE initiation of more than 14\u2009days and up to 60\u2009days may also be beneficial.