Relationship between mean volume voided and incontinence in children with overactive bladder treated with solifenacin: post hoc analysis of a phase 3 randomised clinical trial

This post hoc Poisson regression analysis investigated the relationship between mean volume voided and incontinence episodes/24 h after fixed frequency adjustment in children with overactive bladder from the LION study, a phase 3, double-blind, randomised, placebo-controlled, sequential, dose-titration solifenacin trial. Patients were aged 5–< 12 years with ≥ 4 episodes of daytime incontinence during a 7-day pre-baseline diary period. The dependent variable was the mean number of incontinence episodes/24 h at the end of study. Explanatory variables included treatment, mean number of incontinence episodes/24 h at baseline, and change from baseline to end of study in mean volume voided. Statistical significance and goodness of fit were analysed using the Pearson’s chi-square test. A negative estimate was found between the dependent variable ‘incontinence’ and both mean volume voided and daytime maximum volume voided/micturition (an increase in mean volume voided or daytime maximum volume voided/micturition would lead to a reduction in incontinence; P = 0.0014 and P = 0.0317, respectively). The model was a good fit to the data in both analyses with a Pearson’s chi-square goodness-of-fit criteria of 0.8. Conclusion: Increase in mean volume voided was significantly correlated to reduction in incontinence episodes/24 h in children with overactive bladder treated with solifenacin. This study is registered at ClinicalTrials.gov: NCT01565707.