Baseline severe disability as a predictor of treatment escalation to rituximab in AQP4-IgG-positive NMOSD patients: A retrospective cohort study.

INTRODUCTION

Azathioprine and mycophenolate mofetil remain widely used as first-line immunosuppressive therapies for neuromyelitis optica spectrum disorder (NMOSD) in resource-limited settings. However, a subset of patients experience ongoing disease activity or treatment intolerance requiring escalation to rituximab. Identification of clinical factors associated with treatment escalation may improve treatment strategies.

OBJECTIVES

To identify clinical factors associated with escalation from azathioprine and mycophenolate mofetil to rituximab in AQP4-IgG-positive NMOSD patients.

METHODS

We conducted a retrospective cohort study of AQP4-IgG-positive NMOSD patients treated at the Neurological Institute of Thailand between 2019 and 2024. Patients initially treated with azathioprine or mycophenolate mofetil were followed until escalation to rituximab or last follow-up. Baseline demographic, clinical, and laboratory variables were analyzed using logistic regression to identify factors associated with treatment escalation.

RESULTS

Among 173 patients, 35 (20.23%) required escalation to rituximab. In multivariable analysis, baseline severe disability (EDSS ≥6 prior to first-line therapy) was independently strongly associated with treatment escalation to rituximab (OR 18.19, 95% CI 2.22-148.95; p=0.007). Other demographic and laboratory variables were not independently associated.

CONCLUSION

Baseline severe disability was strongly associated with subsequent escalation to rituximab. Early identification of high-risk patients may support more individualized treatment strategies and inform future policy decisions in resource-limited healthcare systems.