Long term continuation with repeated Botulinum toxin A injections in people with neurogenic detrusor overactivity after spinal cord injury.

[STUDY DESIGN] Retrospective chart study.

[OBJECTIVES] The aim was to examine continuation of treatment of individuals with spinal cord injury including myelomeningocele and neurogenic detrusor overactivity, treated with repeated intra-detrusor Botulinum toxin A injections, and to investigate factors associated with discontinuation of treatment.

[SETTING] Rigshospitalet, Denmark METHODS: This study included 128 individuals with spinal cord injury and neurogenic detrusor overactivity, who were offered repeated Botulinum toxin A injections between 2001 and 2018. Continuation rates of the treatment were estimated using Kaplan Meier analysis. A Cox proportional hazard analysis was used to investigate factors predictive of discontinuation.

[RESULTS] A total of 1156 treatments were performed. The median number of treatments was six (IQR 9, range 1-51), and median follow-up was 10.6 years (IQR 8.5, range 0-16.9). All urodynamic parameters changed significantly after the first treatment (p < 0.001). The continuation group had significantly higher mean maximum bladder capacity after the first injections compared with the discontinuation group, with a mean difference between the groups of 84.5 mL (95% CI 4.7-164.2) (p = 0.038). The probability of continuing treatments after 5 years was 59% (95% CI 50.0-67.8) and 50% (95% CI 40.1-59.3) after 10 years. Individuals aged 31-50 years were more likely to continue treatment compared with those aged >50 years (95% CI 0.21‒0.79) (p = 0.008). No other factors predicted discontinuation.

[CONCLUSIONS] This long-term follow-up study showed that 50% of people with spinal cord injury starting intra-detrusor Botulinum toxin A for neurogenic detrusor overactivity are still receiving injections after 10 years.