Multimodal Biomarker and Ultrasound Profiling in Women with Overactive Bladder: A Prospective Case-Control Study.

INTRODUCTION AND HYPOTHESIS: Overactive bladder (OAB) remains a symptom-based diagnosis with limited objective tools for biological characterization. This study evaluated a multimodal profile of OAB by simultaneously assessing urinary and serum biomarkers and ultrasonographic bladder parameters in women with OAB. METHODS: In this prospective case-control study, 80 women were enrolled (40 OAB patients [OAB-V8 score ≥11], 40 age- and BMI-matched healthy controls). Urinary and serum BDNF, NGF, and substance P were measured by ELISA; oxidative stress markers (TOS, TAS, OSI) were analyzed. Bladder wall thickness, detrusor thickness, and bladder resistive index were assessed by ultrasonography. Correlation and multivariable logistic regression analyses evaluated associations with symptom severity and potential confounding by menopausal duration. RESULTS: Urinary and serum BDNF, NGF, and substance P were significantly elevated in OAB (all p < 0.001), as were ultrasonographic bladder wall parameters (all p < 0.001). Serum NGF showed the highest diagnostic accuracy (AUC 1.000), followed by serum BDNF (0.999), urinary BDNF (0.976), and urinary substance P (0.972). Urinary substance P (ρ = 0.929) and urinary BDNF (ρ = 0.916) correlated most strongly with symptom severity. All four principal biomarkers remained independently associated with OAB after adjustment for menopausal duration. A composite urinary-biomarker-plus-ultrasound model showed a numerically, but not statistically, higher AUC than the best single urinary marker (0.999 vs. 0.976; DeLong's test, p = 0.308). CONCLUSIONS: Women with OAB exhibited a distinct multimodal biological profile characterized by neurotrophin activation, oxidative stress imbalance, and structural bladder wall changes. These exploratory findings require external validation in larger prospective cohorts before clinical implementation can be considered.