Use of rituximab and risk of re-hospitalization for children with neuromyelitis optica spectrum disorder

Sabrina Gmuca, Rui Xiao, Pamela F. Weiss, Amy T. Waldman, Jeffrey S. Gerber

Treatment algorithms for neuromyelitis optica spectrum disorder (NMOSD) vary, and sparse data exist regarding the impact of initial treatments on disease course. We aimed to determine whether administration of rituximab during first hospitalization reduces 1-year readmission rates. We conducted a retrospective cohort study of subjects with NMOSD using the Pediatric Health Information System database from 2005-2015. Subjects were ages 1 to 21 years who received glucocorticoids and an ICD-9-CM code indicating neuromyelitis optica (NMO) during first hospitalization. All subjects had at least 12 months of continuous enrollment. The primary exposure was ≥1 rituximab dose during first hospitalization. We tested for the association of rituximab use with all-cause re-hospitalization, the primary outcome, using survival analysis. Re-hospitalization was considered if a hospital admission occurred > 30 days after initial discharge with exclusion of admissions with re-dosing of rituximab and data were censored at 12 months. Secondary outcomes included time to and median duration of re-hospitalization using 25th percentiles of survival time and the Wilcoxon-rank sum test, respectively. Of 180 subjects who met inclusion criteria, 71.7% were female and the median age was 13 years (IQR: 10, 15). 52 subjects (28.9%) received rituximab during first hospitalization, and there was an increasing trend in rituximab use over time (p<0.01). Overall, 36.7% of children were readmitted and time to readmission was a median of 365 days (IQR: 138, 365). Rituximab exposure was not associated with re-hospitalization (adjusted HR: 0.71: 95% CI: 0.38, 1.34) nor a reduced time to re-hospitalization. Median duration of re-hospitalization was 2 days shorter in the rituximab exposed group (p=0.02). Receipt of physical therapy, a surrogate marker for neurologic impairment, during first hospitalization was associated with re-admission within 12 months (adjusted HR: 4.81; 95% CI: 1.14, 20.29). Among children with NMOSD, first-line administration of rituximab was not associated with risk of or time to re-hospitalization. Rituximab use was found to be associated with a shorter duration of re-hospitalization. Need for physical therapy during first hospitalization was independently associated with an increased risk of re-admission.