Low bladder capacity is an important predictor for comorbidity of interstitial cystitis with Hunner's lesion in patients with refractory chronic prostatitis/chronic pelvic pain syndrome.

Objective: To evaluate the predictive factors for comorbidity of Hunner-type interstitial cystitis in patients with chronic prostatitis/chronic pelvic pain syndrome using urethrocystoscopy.

Methods: Thirty-two male patients were included in this study. Between April 2012 and April 2016; they were diagnosed with chronic prostatitis/chronic pelvic pain syndrome according to the National Institutes of Health classification. Their symptoms were not improved by 3 months of behavioral and pharmacological therapies. They all underwent narrow band imaging-assisted urethrocystoscopy to assess whether the presence of Hunner's lesions correlated with other variables.

Results: Thirteen out of 32 patients (41%) had Hunner's lesions. Of the variables, maximal voided volume per micturition (106 ± 29 mL vs 171 ± 61 mL) and bladder capacity (267 ± 121 mL vs 407 ± 137 mL) were significantly smaller in patients with Hunner's lesions compared to those without. Other variables, apart from age, were not significantly different. Furthermore, patients with voided volume less than 150 mL were more likely to have Hunner's lesions than those with voided volume exceeding 150 mL.

Conclusions: Hunner-type interstitial cystitis is a common comorbidity among patients with refractory chronic prostatitis/chronic pelvic pain syndrome. In cases where voided volume is small, performing narrow band imaging-assisted urethrocystoscopy would be very helpful for detecting bladder mucosal changes such as Hunner's lesions.