Objective To determine the prevalence of interstitial cystitis in Japan, and to analyse the diagnostic criteria and treatments most commonly used by Japanese urologists.
Materials and methods Questionnaires were sent to 300 urologists at major hospitals, including medical university hospitals, throughout Japan, asking about the number of patients with interstitial cystitis, its epidemiology, diagnosis and therapy.
Results The prevalence of interstitial cystitis was 1.2 per 100 000 patients and 4.5 per 100 000 female patients; the male/female ratio was 1 : 5.8. Most Japanese urologists used two or more diagnostic criteria; bladder biopsy was the most common diagnostic method. Dimethyl sulphoxide instillations and corticosteroids were the most frequently used therapies.
Conclusion The prevalence of interstitial cystitis in Japan is markedly lower than that reported in Europe and North America. The reasons for this difference were not only racial but also the lack of awareness among Japanese urologists and patients about interstitial cystitis.