Urinary nerve growth factor level could be a biomarker in the differential diagnosis of mixed urinary incontinence in women

Abstract

To measure urinary nerve growth factor (NGF) levels in women with stress urinary incontinence (SUI) and overactive bladder symptoms (OAB) and to assess whether urinary NGF levels can be a biomarker of detrusor overactivity (DO) in women with mixed urinary incontinence. Urinary NGF levels were measured in 38 women with urodynamic SUI (USI) with OAB, in 26 with urodynamic DO but no SUI, in 21 with persistent USI after anti-incontinence surgery, in 15 with de novo DO, and in 31 normal control subjects. All participants had a video-urodynamic study for the differential diagnosis of the underlying causes of UI. Urinary NGF levels were measured using an enzyme-linked immunosorbent assay and were compared among all subgroups, and corrected using urinary creatinine (Cr) levels. The mean (sem) urinary NGF/Cr levels were low both in controls, at 0.06 (0.004) and in women with pure USI, at 0.056 (0.037) (P = 0.108). The NGF/Cr levels were significantly higher in women with mixed USI and DO, at 1.00 (0.244), than in controls (P < 0.001) and those with pure USI (P = 0.006), but were similar to the levels in women with pure DO, at 0.58 (0.17) (P = 0.058). The NGF/Cr levels were undetectable in women with persistent USI but were significantly higher in those with de novo DO, at 2.39 (0.90), after anti-incontinence surgery than in controls and those with USI. A urinary NGF/Cr level of >0.05 was found in 9% of women with USI, 77% with DO, 81% with mixed USI and DO, and 80% with de novo DO. The urinary NGF level could be a potential biomarker of DO in women with mixed UI.