Potassium sensitivity test predicts hydrodistention efficacy in patients with bladder pain syndrome/interstitial...

To determine the possible role of potassium sensitivity test (PST) in predicting the success of hydrodistention (HD) in patients with bladder pain syndrome/interstitial cystitis (BPS/IC).

Patients who underwent PST before diagnostic cystoscopy and HD were evaluated to collect data regarding the visual analog score (VAS) to assess pain, the voiding diary for frequency of urination/nocturia, mean urine volume per void, interstitial cystitis symptom index, and problem index before HD. Patients were requested to provide the VAS of pain at 1 month and 6 months post-HD. A reduction 2 or more on the VAS of pain was considered as a response adequate to be noted.

The median age of the patients was 46 years. The PST was positive for 27 patients (27/39; 69.2%). At 1 month post-HD, out of the 27 patients with positive PST, 23 (85.2%) were found to have been responsive to HD and 4 (14.8%) were non-responsive. Of the 12 (12/39; 30.8%) patients who showed a negative PST, 7 (58.3%) were non-responsive and 5 (41.7%) were responsive to HD. A logistic regression analysis revealed that PST (p=0.009) was the only parameter that was able to predict HD efficacy at 1 month post-HD.

PST was found to be a predictive factor for the short-term efficacy of HD. BPS/IC patients with positive PST are likely to be more susceptible to the damage of mucosal afferent nerve endings, which results in them benefiting from HD to a greater degree.