Epidemiology, Natural History, and Outcomes of Primary Sclerosing Cholangitis: A Systematic Review of Population-based Studies.

BACKGROUND & AIMS:The aim of this study was to quantify the global epidemiology of primary sclerosing cholangitis (PSC), alongside the incidence of liver transplantation, cancer, and death, through robust systematic review of population-based data. METHODS:We searched MEDLINE and EMBASE up to and including June 30, 2020 to identify population-based studies reporting the incidence and/or prevalence of PSC. Studies that did not report original data, or of exclusively pediatric-onset disease (diagnosis age <16 years) or exclusively PSC-associated with inflammatory bowel disease were excluded. RESULTS:Of 4922 published studies, 17 fulfilled inclusion criteria; 16 documenting incidence and 14 prevalence. The highest reported incidence of PSC was reported in Northern Europe (Finland, 1.58 and Norway, 1.3 per-100,000 population, respectively) and North America (Minnesota, 1.47); with the lowest being observed across the Mediterranean Basin (Italy, 0.1). Prevalence ranged from 31.7 in Finland and 23.99 in Minnesota, to 1.33 in Singapore and 0.0 in Alaska. Of studies reporting temporal occurrence, an increase in disease incidence was observed across North America and Northern Europe (4 studies), alongside an increase in prevalence over time (4 studies). The incidence and risks for clinical outcomes were presented by 9 of the included studies. Median transplant-free survival ranged from 9.7 (United States) to 20.6 years (Netherlands), with standardized mortality ratios of 2.5 and 4.2 compared with the control population. The standardized incidence of cholangiocarcinoma ranged from 235 (Finland) to 398 (Netherlands). CONCLUSIONS:Estimates of PSC incidence and prevalence vary, with most studies conducted in North America and Western Europe; the latter showing a steady increase in disease occurrence over time. Further research is needed to understand changes in disease epidemiology, including etiological drivers, the implications of rising case burden on health care policy, and better appreciation of PSC in the developing world.