Natural history and prognostic models in primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by inflammation and fibrosis of the intra- and extra-hepatic bile ducts. Despite the recognition of immunological and genetic alterations cited as factors in its pathogenesis, the exact cause for PSC remains unknown. Observational cohort studies, however, have demonstrated that PSC is a progressive disease culminating in liver failure or death. Natural history assessment in PSC, however, has been complicated by variable rates of disease progression and the impact of clinical symptoms upon initial presentation. The development of mathematical models by multivariable regression techniques (most notably Cox proportional hazards regression) has allowed for an improved description of overall survival on an individual basis among patients with PSC. Additionally, these models have also been employed for determining the optimal selection and timing for liver transplantation when advanced disease is imminent.