Table 2:
Summary of Biomarker Studies for Overactive Bladder (OAB)
| Biomarker | # Studies | Summary of Effect |
|---|---|---|
| NGF | 40 | Multiple poorer quality studies showing associations between urinary NGF and OAB; higher quality studies do not show differences between NGF and controls when controlling for covariates, especially age. Limited data showing that serum NGF may be elevated in a subset of patients with OAB and metabolic syndrome, but not in controls or other types of OAB. Two studies in bladder tissue fail to demonstrate differences in urothelial NGF between OAB and controls. |
| BDNF | 7 | Multiple poorer quality studies showing associations between BDNF and OAB; higher quality studies do not show differences after controlling for potentially confounding factors |
| PGE2 | 7 | Mixture of effect; 4 poor quality studies showing an association while 3 poor quality studies do not |
| ATP | 6 | Variable results in 3 studies; 3 additional studies performed using urodynamic fluid (not solely in urine) |
| CRP | 13 | Conflicting results are noted in multiple analyses using regression to control for potentially confounding variables. |
| Other inflammatory | 17 | Overall poor quality studies that do not control for confounders and often do not adjust for multiple testing; variable associations noted (see Supplementary Tables 2,5) |
| Receptors/Channels | 11 | Multiple studies showing higher M3 muscarinic receptor expression/density and lower β−3 adrenergic receptor expression in OAB; no differences in M2 receptors between OAB and controls. More TRPV1 receptors in OAB; variable results with regards to purinergic receptors and gene for beta 3 adrenoreceptor (ADR3B) |
| Gene expression/proteomic | 2 | Small sample sizes, lack of adjustment for confounders, and lack of adjustment for false-discovery rate limit conclusive results |
| Metabolomic | 2 | Metabolites may be useful in phenotyping (understanding subtypes of OAB) |
| Microbiome | 9 | Mostly association studies; require further investigation with longitudinal sampling and studies that control for potentially confounding factors |
NGF: nerve growth factor, BDNF: brain derived neurotrophic factor; PGE2: prostaglandin E2; ATP: adenoside triphosphate; CRP: C-reactive protein
Individual study details are listed in Supplemental Table 2