Mortality and the risk of malignancy in autoimmune liver diseases: a population-based study in Canterbury, New Zealand.
Population-based quantitative data on the mortality and cancer incidence of autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC) are scarce. Our aim was to systematically investigate the survival and risk of malignancy on population-based cohorts of AIH, PBC, and PSC in Canterbury, New Zealand. Multiple case-finding methods were employed, including searches of all public and private, adult and pediatric outpatient clinics, hospital notes, laboratory, radiology, and pathology reports. Cases that fulfilled standardized diagnostic criteria were included. Kaplan-Meier survival estimates, standardized mortality ratios (SMR), and standard incidence ratios (SIR) for malignancy were calculated. A total of 130 AIH, 70 PBC, and 81 PSC patients were included contributing to 1,156, 625, and 613 person-years at risk, respectively. For AIH, PBC, and PSC cohorts, SMRs for all-cause mortality were 2.1 (95% confidence interval [CI] 1.4-3.1), 2.7 (95% CI 1.7-4.0), and 4.1 (95% CI 2.6-6.3), SMRs for hepatobiliary mortality were 42.3 (95% CI 20.3-77.9), 71.2 (95% CI 30.7-140.3), and 116.9 (95% CI 66.8-189.8), SIRs for all cancers were 3.0 (95% CI 2.0-4.3), 1.6 (95% CI 0.8-2.9), and 5.2 (95% CI 3.3-7.8), and SIRs for extrahepatic malignancy were 2.7 (95% CI 1.8-3.9), 1.6 (95% CI 0.8-2.9), and 3.0 (95% CI 1.6-5.1), respectively. This is the first population-based study to examine and compare the survival and cancer incidence in AIH, PBC, and PSC in the same population. The mortality for all three cohorts was significantly increased due to liver-related death, demonstrating the inadequacy of current management strategies. The risk of hepatic and extrahepatic malignancy was significantly increased in AIH and PSC patients.