Incidence and prevalence of primary sclerosing cholangitis in a defined adult population in sweden

Abstract

Population-based studies on the epidemiology of primary sclerosing cholangitis (PSC) are sparse. The aim of the present study was to investigate prevalence and temporal trends in the incidence of PSC 1992-2005 in an adult population in Västra Götaland, a region in southern Sweden with a defined population of about 1.5 million. Patients with PSC aged 18 years or above were identified through a computerized search for diagnostic codes. A total number of 199 incident cases fulfilling Mayo criteria for PSC were identified through retrospective validation of clinical records. Temporal trends in the incidence of PSC were investigated by Poisson regression and expressed as average annual percent change (AAPC) with a 95% confidence interval (CI). The point prevalence of PSC on December 31, 2005, was 16.2/100,000 in the total adult population (men, 23.7/100,000; women, 8.9/100,000). The annual incidence was 1.22/100,000 in the total adult population (men, 1.78/100,000; women, 0.69/100,000). The overall incidence rate of PSC increased significantly over the investigation period (AAPC 3.06, 95% CI 0.01-6.20). Stratified analysis revealed significantly increasing trends for inflammatory bowel disease (IBD)-associated PSC (AAPC 7.01, 95% CI 0.24-14.24) and large duct PSC (AAPC 6.32, 95% CI 0.03-13.02) in women and for PSC without IBD (AAPC 9.69, 95% CI 0.82-19.33) and small duct PSC (AAPC 17.88, 95% CI 0.95-40.25) in men. This is the first study to report a significantly increasing trend in the incidence of PSC. The prevalence of PSC at the end of the study period is the highest reported to date. This implies that the medical burden of PSC may be higher than estimated previously.