Urinary Nerve Growth Factor as a Potential Biomarker of Treatment Outcomes in Overactive Bladder Patients

PURPOSE: The aim of this study was to investigate urinary nerve growth factor (NGF) as a biomarker of treatment efficacy and recurrence in overactive bladder (OAB) patients. METHODS: We enrolled 189 OAB subjects who visited our outpatient clinic from February 2010 to February 2015. All subjects with OAB received antimuscarinic treatment. A 3-day voiding diary and questionnaire were collected from each patient. Urinary levels of NGF were evaluated at baseline, the beginning of antimuscarinic treatment, and the end of antimuscarinic treatment. Urinary NGF was normalized to urine creatinine (Cr). Between-group comparisons of baseline characteristics were made using the Mann-Whitney U-test. Multivariate logistic regression analyses were used to predict responses to anticholinergic treatment and recurrence. The Wilcoxon signed-rank test with the Bonferroni correction was used for intragroup comparisons. A receiver operating characteristic curve was used to analyze the utility of this biomarker. RESULTS: Urinary levels of NGF/Cr tended to decrease in patients who responded to treatment (n=62), but this was not significant (P=0.260). Urinary NGF levels were higher at baseline in patients who did not experience recurrence than in those who did (P=0.047). In those who did not experience recurrence (n=29), urinary NGF/Cr decreased at the end of treatment compared to baseline, and this reduction was maintained at 12 weeks after the end of treatment (P<0.05). CONCLUSIONS: Urinary NGF is a potential biomarker for predicting the outcome of antimuscarinic treatment in OAB patients. This may provide useful information when deciding to stop antimuscarinic treatment in responders.