Epidemiology and natural history of primary biliary cirrhosis in a U.S. community

Background & Aims: The epidemiology of primary biliary cirrhosis (PBC) has not been studied systematically in the United States. We report the incidence and prevalence of this condition in the general population. We also examined the validity of the Mayo natural history model for PBC among these unselected patients from the community. Methods: The Rochester Epidemiology Project entails a computerized index of diagnoses from the health care encounters of residents of Olmsted County, Minnesota. For potential cases identified using this database, the complete (inpatient and outpatient) medical records were reviewed to verify the diagnosis and extract information necessary for the application of the Mayo model. We estimated the incidence and prevalence of PBC in this population and compared the actual survival of patients with PBC in the community with the survival predicted for PBC patients by the Mayo natural history model. Results: The age-adjusted (to 1990 U.S. whites) incidence of PBC per 100,000 person-years for years 1975-1995 was 4.5 (95% confidence interval [CI], 3.1-5.9) for women, 0.7 (95% CI, 0.1-1.3) for men, and 2.7 (95% CI, 1.9-3.5) overall. The age- and sex-adjusted prevalence per 100,000 persons as of 1995 was 65.4 (95% CI, 43.0-87.9) for women, 12.1 (95% CI. 1.1-23.1) for men, and 40.2 (95% CI, 27.2-53.1) overall. The Mayo natural history model accurately predicted the actual survival of these patients. Conclusions: This first description of the epidemiology of PBC in the United States indicates that its incidence and prevalence in this country are among the highest reported. Outcomes among these unselected patients from a community population further validated the Mayo natural history model of PBC.