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

Abstract

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 atClinicalTrials.gov: NCT01565707.What is known:• Mean volume voided per micturition is used as an indicator of treatment efficacy, with increases noted as number of incontinence episodes (and micturition frequency) decrease.• The relationship between mean volume voided and incontinence episodes is not clearly understood.What is new:• Increase in mean volume voided significantly correlated to reduction in incontinence in solifenacin-treated children with overactive bladder (Poisson regression model analysis).• Compared with placebo, solifenacin-treated children had a lower predicted number of incontinence episodes/24 h.