Long-Term Outcome of Aquaporin 4-Positive Neuro Myelitis Optica Spectrum Disorder and Efficacy of Long-Term Immunosuppression – A Single-Center Study from South India

INTRODUCTION: Aquaporin 4 (AQP4) neuromyelitis optica spectrum disorder (NMOSD) is a demyelinating disorder of the central nervous system. Following an acute attack, morbidity is incapacitating, and long-term immunotherapy is the rule. OBJECTIVES: This study assesses the clinical profile, annualized relapse rate (ARR), effectiveness, and adverse effects of long-term immunosuppression in Indian patients with AQP4+NMOSD. METHODS: This is an ambispective observational study of AQP4+NMOSD patients diagnosed in Nizam's Institute of Medical Sciences, Hyderabad, India, over 10 years between January 2010 and December 2019. Clinical and demographic data and details of immunosuppressive drugs were noted. RESULTS: Our study had 52 patients. Forty-six (87%) were female. The mean age of patients was 31.82 years. The mean expanded disability status scale at the time of onset of the disease and last follow-up was 6.63 and 3, respectively. The median pretreatment ARRs of the patients before initiation of long-term immunosuppression for methotrexate (MTX), azathioprine (AZA), mycophenolate (MMF), and rituximab (RTX) were 2, 2, 1, and 0.67, respectively. The median post-treatment ARRs of the patients on MTX, AZA, MMF, and RTX at the last follow-up were 0.36, 0.16, 0, and 0, respectively. The relapse-free interval was better with RTX, followed by AZA and MMF, on the Kaplan-Meier curve. CONCLUSION: This is a single-center study from South India with a long follow-up period, adding to the existing body of literature that is available in the management of NMOSD. In our study, patients on RTX had better outcomes, followed by AZA, MMF, and MTX. The threshold to start RTX can be low in patients with NMOSD.