Prevalence and incidence of interstitial cystitis in a managed care population

Purpose: We calculated the prevalence and incidence of physician diagnosed interstitial cystitis (IC) in men and women in a managed care population in the Pacific Northwest. Materials and Methods: A computer search of the Kaiser Permanente Northwest (Portland, Oregon) database was performed for January 1998 to May 2002. The prevalence of IC in patients 25 to 80 years old was calculated using the 4 definitions of 1) patients assigned a diagnosis of IC, 2) patients assigned a diagnosis of IC without any of the consensus IC exclusion criteria, 3) patients who had also had undergone cystoscopy and 4) patients who had specifically undergone cystoscopy with hydrodistention for IC. A second database search was performed 1 year later (May 2003) to identify incident cases of IC. Results: The prevalence of IC was 197 per 100,000 women and 41 per 100,000 men for definition 1, 158 per 100,000 women and 28 per 100,000 men for definition 2, 99 per 100,000 women and 19 per 100,000 men for definition 3, and 45 per 100,000 women and 8 per 100,000 men for definition 4. Using definition 2 the 1-year incidence of IC was 21 per 100,000 women and 4 per 100,000 men. The female-to-male ratio for each estimate was 5:1. Conclusions: The prevalence and incidence of interstitial cystitis is significantly higher for women and men than previously published estimates. Men account for a higher proportion of patients with IC than has previously been recognized.