Emerging Urinary Biomarkers for Diagnosis, Phenotyping, and Treatment Monitoring in Female Overactive Bladder: A Systematic Review.

INTRODUCTION AND HYPOTHESIS: Overactive bladder (OAB) syndrome, characterised by urinary urgency, frequency, and nocturia can significantly impacts patients' quality of life. Current diagnosis is clinical, but complex cases often require invasive urodynamic studies (UDS), which are costly, subjective, and carry risks like discomfort and infection. Therefore, we hypothesise that urinary biomarkers could serve as noninvasive diagnostic tools for OAB. Establishing a reliable biomarker profile could ultimately lessen the reliance on invasive US, provided clinical validity is confirmed.

METHODS

Following PRISMA guidelines and registered under PROSPERO (ID: CRD420251026279), a comprehensive search across six major databases was conducted from their inception until September 2025, yielding 39 studies for qualitative analysis.

RESULTS

This qualitative review identified several promising biomarkers for OAB diagnosis. Notably, NGF and BDNF consistently emerged as elevated in OAB patients and were responsive to treatment. Additionally, TNF-α, MIP-1β, Tie2, and CCL2 showed diagnostic potential, with TNF-α and MIP-1β particularly useful for differentiating OAB from interstitial cystitis/bladder pain syndrome (IC/BPS) and urinary tract infections (UTIs). However, limitations such as variability in measurement protocols and a lack of specificity for certain biomarkers (e.g. MMP-1, 8-OHdG) were noted.

CONCLUSIONS

Urinary biomarkers offer a promising noninvasive approach to diagnosing OAB. Further validation of promising markers, particularly NGF, BDNF, TNF-α, MIP-1β, and CCL2, could lead to individualised therapies. While promising, the routine replacement of UDS remains an aspirational goal dependent on future large-scale validation.