Functional bladder capacity can reflect the bladder condition and treatment outcome in patients with interstitial cystitis/bladder pain syndrome.

PURPOSE: Interstitial cystitis/bladder pain syndrome (IC/BPS) is a complex chronic condition characterized by bladder pain and urinary symptoms. Functional bladder capacity (FBC) in daily life, cystometric bladder capacity (CBC) during urodynamic studies, and maximum bladder capacity (MBC) under anesthesia have distinct clinical implications for diagnosing and prognosing patients with IC/BPS. This study aims to assess the role of bladder capacity measurements in evaluating these patients.

METHODS

We conducted a retrospective cohort study involving 198 patients with IC/BPS without Hunner’s lesions treated with intravesical platelet-rich plasma (PRP) injections. Bladder capacity was assessed by: FBC via three-day voiding diary, CBC via videourodynamics, and MBC via cystoscopic hydrodistention under anesthesia. We used Pearson correlations and multiple linear regression analyses to examine the association of bladder capacity measurements with IC symptom severity and PRP treatment outcomes (GRA).

RESULTS

FBC significantly correlated with MBC (r = 0.301, p < 0.01), symptom severity (ICSI: r = − 0.360, p < 0.01), and treatment outcome (GRA at 6 months: r = 0.251, p < 0.01). Multiple regression analysis revealed that sensation of a full bladder (β = 0.357, p = 0.044), MBC (β = 0.292, p = 0.004), and GRA (β = 0.189, p = 0.044) were significantly associated with FBC.

CONCLUSION

FBC is a clinically relevant measure of bladder condition and symptom burden in IC/BPS, demonstrating strong associations with MBC and treatment outcomes. Given its non-invasive nature and ease of measurement, FBC should be considered the primary assessment tool for IC/BPS among these capacity measures.