Sensitivity and specificity of urinary and serum neurotrophins in the diagnosis of neurogenic detrusor overactivity in multiple sclerosis

Lower urinary tract dysfunction is common among neurological patients. Traditionally, the basic method of diagnosis is a complex urodynamic study. In recent years, many studies have focused on the search for new non-invasive diagnostic modalities. In particular, neurotrophins are considered as potential biological markers of a neurogenic bladder. Aim. To estimate the sensitivity and specificity of the serum and urinary nerve growth factor (NGF) and brain neurotrophic factor (BDNF) in MS patients as markers of detrusor overactivity. Materials and methods. The study comprised 20 patients with multiple sclerosis, who complained of voiding problems. The control group consisted of 20 people without neurological diseases, lower urinary tract symptoms and detrusor overactivity estimated by filling cystometry. Apart from standard laboratory tests, diagnostic evaluation included a complex urodynamic study, ultrasound of the urinary tract, cystoscopy, testing serum and urinary NGF and BDNF using the enzyme immunoassay. The diagnostic significance of neurotrophins was evaluated using ROC analysis. Results. According to the ROC analysis, the diagnostic sensitivity and specificity of serum NGF as a marker of detrusor hyperactivity was 57% and 93%, respectively (for serum NGF ≥26 pg/ml). The quality of the test according to the expert scale of AUC values was «very good» (AUC=0.806). Detecting NGF in patients’ urine was less effective. The sensitivity and specificity were 52% and 40%, respectively (for NGF ≥6 pg/ml). The quality of the test according to the expert scale of AUC values was «average» (AUC=0.64). The serum BDNF demonstrated high sensitivity (90%) and low specificity (23%), AUC=0.56. The urinary BDNF was more informative, (AUC=0.65). The combination of all four markers provides a sensitivity of 85.7% and a specificity of 66.7% (AUC=0.824). Conclusions. Testing serum and urinary neurotrophins in patients with multiple sclerosis can be used to diagnose detrusor overactivity. The NGF is a highly specific biomarker, while the BDNF is highly sensitive. Combined testing for serum NGF and BDNF is most informative.

neurotrophins, multiple sclerosis, neurogenic bladder