Efficacy and predictive factors of clinical response to hyaluronic acid ＋ chondroitin sulfate bladder instillations for the treatment of BPS/IC

To assess the efficacy of intravesical hyaluronic acid and chondroitin sulfate (HACS) instillations in treating patients with bladder pain syndrome/interstitial cystitis (BPS/IC), as well as to identify predictive factors for clinical response. Patients diagnosed with BPS/IC and treated with Ialuril® (HACS) bladder instillations between January 2018 and August 2020 were included. Data collected included Visual Analog Scale (VAS) scores, number of pain episodes, 3-day frequency volume chart measurements (at baseline and last follow-up), Patient Global Impression of Improvement (PGI-I) questionnaire responses, age, history of urinary tract infections (UTIs), and endoscopic findings from cystoscopy with hydrodistension. Statistical analyses included Mann–Whitney's non-parametric U-test and chi-square test with a 95% confidence interval (p≤ 0.05) to identify predictive factors of treatment success. A total of 104 patients were treated with a median follow-up of 29 months (IQR 14-40), predominantly female with a mean age of 60 ± 16 years. At the last follow-up, there was a median reduction of 1 point in the VAS score (IQR 1-1), whilst only 20% experienced a reduction of ≥ 2 points. A statistically significant correlation was observed in the reduction of days with pain per month before and after treatment (ΔDPV) (median reduction: 6 days, IQR 2-7, p< 0.001). No adverse events were reported during treatment. Regarding prognostic factors, three statistically significant correlations were found: between PGI-I success and age (p=0.050), between ΔVAS score and recurrent UTIs (p=0.044), and between ΔDPV and recurrent UTIs (p=0.04). The study did not demonstrate any significant reduction of VAS score or diurnal and nocturnal voiding frequency after treatment, on the contrary it did show a reduction in the number of days with pain. Consequently, 88.3% of patients reported positive subjective improvement on the PGI-I questionnaire, and none discontinued treatment. Endoscopic findings did not appear to correlate with treatment response. Age and the presence of recurrent UTIs may influence the response to intravesical HACS therapy in terms of PGI-I, VAS score, and reduction in days with pain.