Background: Neuromyelitis optica spectrum disorders (NMOSD) are an inflammatory autoimmune clinical entity that involves the central nervous system and is characterized by episodes of optic neuritis (ON) and transverse myelitis (TM), which generally have poor or no recovery.
Objective: To describe risk factors related to relapse after the start of first immunosuppressive treatment (FIT) in patients with NMOSD.
Methods: We performed a retrospective case-control study. We included patients from the demyelinating diseases registry at INCMNSZ neurology department. We selected patients >18 years old that met the 2015 NMODS international consensus diagnostic criteria. We obtained clinical and demographic variables, Anti-Aquaporine 4 antibody (Anti-AQP4) status, and treatment used. We conducted a bivariate analysis (Chi2 and Odd Ratio [OR]) to determine the association of these variables and relapse after FIT. Significant variables were analyzed using a binary logistic regression model.
Results: 95 patients were analyzed. Eighty-six percent of patients were female. Median age was 45.5+14.9. The average disease duration was 6.8+4.6 years with an average of 2.3+1.2 relapses. In the bivariate analysis, age < 50 years (p=0.037, OR 2.82 [1.044-7.665]), positive anti-AQP4 status (p=0.027, OR 2.698[1.108-6.574]), either simultaneous or sequential ON/TM coexistence, (p=0.004, OR 4.222[1.657-10.765]) and azathioprine as FIT (p=<0.001, OR 5.18[2.023-13.151]) had a significant association. In the binary logistic regression model, azathioprine as FIT (p=0.002, OR 5.564[1.890-16.38 1]), ON/TM coexistence (p=0.007, OR 4.648[1.527-14.149]) and age <50 years (p=0.020 OR 4.322 [1.263-14.795]) remained statistically significant, however, positive anti-AQP4 status (p=0.143) did not.
Conclusions: In this study, patients with NMOSD that receive azathioprine as FIT, are < 50 years old and have ON/TM coexistence had a greater risk of disease relapse after FIT. Simultaneous steroid use and dose and adherence to azathioprine therapy are motive of further study.