Introduction and hypothesis: The purpose of this study was to investigate change in bladder capacity as a measure of response to combined intravesical dimethyl sulfoxide (DMSO) and triamcinolone instillations for the treatment of newly diagnosed bladder pain syndrome/interstitial cystitis (BPS/IC).
Methods: 141 newly diagnosed women were identified retrospectively. 79 were treated with weekly DMSO/triamcinolone instillations. Change in bladder capacity with bladder retrofill, daytime urinary frequency, nocturia episodes per night, and Likert scale symptom scores were reviewed. Wilcoxon signed-rank tests, Wilcoxon rank-sum tests, Spearman's rank correlations, COX regression analysis, and a Kaplan-Meier survival curve were performed.
Results: Significant changes (median (25(th)-percentile to 75(th)-percentile) were noted for bladder capacity (75 mL (25 to 130 mL), p < 0.0001), inter-void interval (0 hrs (0 to 1 hour), p < 0.0001), nocturia episodes per night (-1 (-2 to 0), p < 0.0001), and aggregate Likert symptom scores (-2 points (-5 to 0), p < 0.0001). Percent change in bladder capacity correlated positively with percent change in inter-void interval (p = 0.03) and negatively with percent changes in nocturia (p = 0.17) and symptom scores (p = 0.01). Women without detrusor overactivity (DO) had greater percent changes in capacity than women with DO (62.5 % vs. 16.5 %, p = 0.02). 61.3 % of patients were retreated with a 36 weeks median time to retreatment and no difference in time to retreatment based upon DO. Greater capacity was protective against retreatment (hazard ratio = 0.997 [95 % CI 0.994,0.999], p = 0.02).
Conclusions: Percent change in bladder capacity is a useful objective measure of response to intravesical DMSO/triamcinolone for newly diagnosed BPS/IC. Clinical outcomes do not differ based upon presence of DO.