Initial BMI effects on clinical presentation and prognosis in neuromyelitis optica spectrum disorder

OBJECTIVE: To investigate the correlation among body mass index at onset, clinical features, and prognosis in patients with neuromyelitis optica spectrum disorder. METHOD: This retrospective cohort studied patients with neuromyelitis optica spectrum disorder from January 2015 to January 2022, grouping them by body mass index at onset. Demographics and clinical records were reviewed. Anderson–Gill, Kaplan–Meier, and Cox models evaluated the body mass index's effect on relapse risk and long‐term outcomes. RESULTS: Of 246 patients with 799 neuromyelitis optica spectrum disorder attacks study, 36 patients had low, 133 had normal, 77 had high body mass index, with a mean onset age of 40 ± 13 years, and the population was 88% female. The medium follow‐up time was 49 months; AQP4‐IgG was found in 193 (78%) patients. Onset and relapse of area postrema syndrome were less frequent in patients with a normal body mass index. The annual relapse rate after immunosuppressive therapy was significantly lower in patients with a low body mass index. In the multivariable analysis, statistical correlation still existed between body mass index at onset and risk of relapse (HR = 1.03, 95% CI: 1.03–1.03, P < 0.001), risk of severe attack (HR = 0.92, 95% CI: 0.86–0.98, P = 0.013), risk of visual disability (HR = 0.9, 95% CI: 0.81–1, P = 0.047), and overall risk of disability (HR = 0.89, 95% CI: 0.82–0.98, P = 0.015) after adjusting various variables. INTERPRETATION: Lower body mass index at onset was associated with less frequent relapse but poor prognosis.