Efficacy of high-dose vitamin D supplementation vs. solifenacin or standard urotherapy for overactive bladder dry in children: a secondary analysis of a randomized clinical trial.

Purpose: To investigate the efficacy of high-dose vitamin D supplementation (VDS) plus standard urotherapy (SU) in managing pediatric overactive bladder dry (OAB-dry), specifically in children with (1) vitamin D levels between 20 and 35 ng/mL and (2) heightened baseline symptom severity.

Methods: In this secondary analysis of a randomized controlled trial, eligible children (n = 303) were assigned to 8 weeks of VDS + SU group, solifenacin (SOL) + SU group, or SU alone group. The primary outcome was voiding frequency; secondary outcomes included urgency, nocturia, quality of life (QoL), pediatric lower urinary tract symptoms scores, and patient satisfaction.

Results: Among 303 participants, 197 (65%) had vitamin D levels between 20 and 35 ng/mL, and 119 (39%) exhibited heightened baseline symptom severity. In both subgroups, VDS + SU resulted in significantly greater improvements in voiding frequency compared to SOL + SU and SU alone. In the vitamin D subgroup (20-35 ng/mL), the median difference in voids/day between VDS + SU and SOL + SU was 2.0 (95% CI, 1.0 to 3.0; P = 0.003) and 3.2 compared to SU alone (P < 0.001). In the heightened symptom subgroup, the median difference was 3.0 (95% CI, 2.0 to 4.0; P < 0.001) vs. SOL + SU and 5.0 (95% CI, 4.0 to 6.0; P < 0.001) vs. SU alone. The VDS + SU group generally outperformed the other groups in various secondary outcome measures.

Conclusion: High-dose VDS plus SU has significant therapeutic benefit in children with OAB-dry in those with vitamin D levels between 20 and 35 ng/mL and with more severe symptoms, compared to SOL + SU or SU alone.