Prevalence of interstitial cystitis symptoms in a managed care population

Purpose: We calculated the prevalence of symptoms typically associated with interstitial cystitis (IC) in men and women in a managed care population in the Pacific Northwest. Materials and Methods: International Classification of Diseases-9 based queries of the Kaiser Permanente Northwest, Portland, Oregon database were used to identify subjects with IC exclusion criteria, who were excluded from further analysis. A total of 10,000 questionnaires, including 5,000 for women and 5,000 for men, were mailed to subjects with codes indicating bladder symptoms and to those with none of the codes. The questionnaires included questions about the presence of IC symptoms and the O'Leary-Sant interstitial cystitis questionnaire. IC symptoms were defined in 2 ways, that is as 1) pelvic pain at least 3 months in duration plus urgency or frequency at least 3 months in duration and 2) the same criteria plus pain increasing as the bladder fills and/or pain relieved by urination. Results: The prevalence of IC symptoms according to definitions 1 and 2 was 11.2% and 6.2% in women, and 4.6% and 2.3% in men, respectively. Symptoms were long-standing (duration greater than 1 year in 80% of cases) and bothersome (severity score 5 or greater in greater than 50%). Mean O'Leary-Sant interstitial cystitis questionnaire scores were 15.94 in subjects with definition 1 IC symptoms, 18.97 in those with definition 2 IC symptoms and 6.69 in those with no IC symptoms (p <0.001). Symptoms were most common and most severe in subjects previously diagnosed with IC. Conclusions: The prevalence of IC symptoms is 30 to 50-fold higher in women and 60 to 100-fold higher in men than the prevalence of a coded physician diagnosis of IC in the same population. Although these findings are not conclusive, they imply that IC may be significantly under diagnosed.