A survey on clinical practice of interstitial cystitis in Japan

To explore the real-life practice of clinical management of interstitial cystitis (IC) in Japan.

A questionnaire on the number of IC patients, cystoscopic findings, diagnostic methods, and the treatment modalities was sent via e-mail to 114 medical institutions belonging to the Society of Interstitial Cystitis of Japan (SICJ).

Completed questionnaires were returned from 62 institutions (20 university hospitals, 26 general hospitals and 16 clinics), with a response rate of 54%. The median of patient number per institution was 20 and the national number of IC patients was counted as 4,531 in Japan. The number of new patients in 2013 was 7 (median) per institution and calculated as 1,214 in total. The case volume per institution distributed broadly and skewed to a lower volume. The patients were categorized according to cystoscopic findings as either Hunner type IC with Hunner lesions (n=2,066, 45%), non-Hunner type IC with glomerulations on hydrodistension (n=1,720, 38%) or hypersensitive bladder without endoscopic abnormalities (n=304, 7%), excluding unknown (n=441, 10%). The proportion of Hunner type IC was highly variable among the institutions, ranging from 0% to 100% with a median of 29%. As for evaluation, symptom and quality of life (QOL) assessment by questionnaires, frequency volume chart, urinalysis, urine cytology, urine culture, post-void residual measurement, uroflowmetry, ultrasound and cystoscopy were widely adapted. Administration of oral medicines and intravesical instillation therapy were undertaken at 98% and 63% of institutions, respectively. Hydrodistension was commonly performed, totaling in 812 procedures at 53 institutions, while only five cystectomies were reported from four institutions.

The survey estimated about 4,500 IC patients and 2,000 Hunner type IC patients in Japan. It also revealed a wide range of case volume, acceptable adherence to clinical guidelines, and high variability in the proportion of Hunner type IC. The variable proportions of Hunner type IC despite a high performing rate of endoscopy suggest inconsistency in diagnostic criteria for the Hunner lesion.