Incidence of physician-diagnosed interstitial cystitis in Olmsted County: a community-based study

OBJECTIVE To obtain community-based information about the incidence of interstitial cystitis, a chronic disabling condition of the bladder where knowledge is limited because there are no definitive diagnostic criteria. PATIENTS AND METHODS All residents of Olmsted County, MN, USA who had received a physician-assigned diagnosis of interstitial cystitis between 1976 and 1996 were identified through the resources of the Rochester Epidemiology Project. The clinical findings at diagnosis and during the follow-up were ascertained from the community medical records for each study subject. RESULTS In all, 16 women and four men received a diagnosis of interstitial cystitis during the study period. The overall age- and sex-adjusted (95% confidence interval) incidence rate was 1.1 (0.6-1.5) per 100 000 population. The age-adjusted incidence rates were 1.6 per 100 000 in women and 0.6 per 100 000 in men (P = 0.04). The median (range) age at initial diagnosis was 44.5 (27-76) years in women and 71.5 (23-79) years in men (P = 0.26). The median number of episodes of care-seeking for symptoms before the diagnosis was one for women and 4.5 for men (P = 0.03). The median duration from the onset of symptoms until the first diagnosis was 0.06 and 2.2 years in women and men, respectively (P = 0.2). CONCLUSIONS These findings suggest that the incidence of interstitial cystitis in the community is extremely low. Although the gender difference may be real, the trend toward a later diagnosis in men than in women suggests a potential for missed diagnosis in men. This might explain some of the gender difference in the incidence of interstitial cystitis in men and women.