Predictors of disability in a cohort with neuromyelitis optica spectrum

Abstract

Disability in neuromyelitis optica spectrum disorder (NMOSD) is common and can be severe. To determine factors associated with increased disability in NMOSD. Observational, analytical, ambispective study in a cohort of patients with NMOSD between January 2015 and July 2021, using a secondary source to review variables and the expanded disability status scale (EDSS) after onset and a primary source, with a telephone survey for the final EDSS and missing data. Major disability was defined as occurring when the EDSS score was = 6. The analysis was performed by means of logistic regression with SPSS 25®. A total of 125 patients were analysed. The average age at onset was 41 (standard deviation: 14) years, with a female-to-male ratio of 8:1. Of the total sample, 87% (109) were positive for anti-aquaporin antibodies. Optic neuritis (44.8%) and transverse myelitis (39.2%) were the most frequent clinical manifestations at onset. Altogether 71.2% of patients received acute treatment at their first relapse. Mean chronic treatment initiation was 12 months (interquartile range: 3-60) and 44% had difficulties with immunosuppression compliance. Of the total number of patients, 80.8% had relapses and 44% had a final EDSS score = 6. The median baseline-to-final EDSS score was 1 (interquartile range: 0-3), often towards disability accumulation. An association was found between a relapsing course (odds ratio = 3.73; p = 0.011) and a high baseline EDSS (odds ratio = 1.54; p = 0.0001) with increased disability. In the multivariate analysis, with a higher baseline EDSS and a relapsing course disability was 1.6 and 5.3 times more likely to occur, respectively. Disease relapses and high EDSS after the first episode are predictors of disability in NMOSD.