A Prospective, Double-Blind, Randomized Cross-Over Study Evaluating Changes in Urinary pH for Relieving the Symptoms of Interstitial Cystitis
Nguan C, Franciosi LG, Butterfield NN, et al.
BJU Int.2005;95:91–94.
Urine acidity has always been an issue that patients and clinicians consider to be important in the etiology of interstitial cystitis (IC). For instance, is cranberry juice good or bad for the patient with IC? Nguan and associates from the University of British Columbia in Vancouver evaluated whether changing urinary pH had any clinical efficacy in relieving the pain associated with IC.
This was a prospective, randomized, double-blind crossover study conducted with 26 women with IC. The design of the study consisted of crossover instillations of urine at physiologic pH (5.0) and at neutral buffered pH (NaH2PO4 buffered to pH 7.5). Subjective pain was assessed with a visual analogue scale at baseline, after the initial instillation of solution, at washout, and after the crossover instillation. Data were analyzed with repeated-measures analysis of variance.
No statistically significant difference was seen in the mean change from baseline pain score after the instillation of neutral buffered solution (0.50), compared with acidic solution (0.33) (P = .85). Secondary outcomes, including baseline variability and treatment-order effects, were also similar between the two groups.
The data indicate that there is no statistically significant difference in subjective pain scores with the instillation of urine at physiologic pH compared with sodium phosphate-buffered saline in patients with IC. Further work is required to define the role, if any, of urinary pH in the pathophysiology and treatment of IC.