Prevalence of autoimmune liver disease in Alaska natives

Abstract

OBJECTIVE: There is limited information on the prevalence of autoimmune liver disease in nonwhite populations. We conducted a population-based study on the prevalence of autoimmune liver diseases in Alaska natives. METHODS: Clinical records from 1984 to July, 2000 were reviewed to identify Alaska natives with autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), primary sclerosing cholangitis, autoimmune cholangitis, and overlap syndromes of two of the above. AIH was defined as definite or probable, based on criteria established by the International Autoimmune Hepatitis Group. The diagnosis of PBC was based on a positive antimitochondrial antibody of ≥1:40, biochemical evidence of cholestasis, and compatible liver biopsy. Autoimmune cholangitis was defined as PBC but without a positive antimitochondrial antibody. Primary sclerosing cholangitis was diagnosed on the basis of cholangiogram. RESULTS: Seventy-seven patients with possible autoimmune liver disease were identified. Of these, 42 had definite and seven probable AIH. At presentation, 34.7% of patients with AIH presented with acute icteric hepatitis, and 65.3% were asymptomatic. Persons presenting with mild or no symptoms were more likely to have moderate to severe fibrosis on liver biopsy than those presenting with jaundice. Eighteen persons were diagnosed with PBC, five with autoimmune cholangitis, five with overlap syndrome, and none with primary sclerosing cholangitis. The combined point prevalence of AIH Alaska natives was 42.9/100,000 (95% CI = 31–57.7). The prevalence of PBC was 16/100,000 (95% CI = 12.9–25.4). CONCLUSIONS: This population-based study demonstrates that the prevalence rates of AIH and PBC in Alaska natives are comparable with reported rates in other populations.