The Incidence of Chronic Active Hepatitis in Norway: A Retrospective Study

From all departments of internal medicine in Norway information has been collected about new cases of chronic active hepatitis (CAH) diagnosed during 1981. A questionnaire together with copies of histological examination reports and discharge summaries have been carefully examined to ensure that established diagnostic criteria were fulfilled. Of the 63 reported cases, 58 were recorded as CAH. An aetiological agent was identified in nine cases; six were HBsAg-positive, two were alcohol-induced, and one drug-induced. The other 49 cases were assumed to be idiopathic. The incidence of CAH of all causes was 1.41 per 100,000; of idiopathic CAH, 1.19 per 100,000; and of HBsAg-positive CAH, 0.15 per 100,000. The mean age was 51 years, and a third of the patients in the idiopathic group were 65 years or older at presentation. In this group about 71% of the patients had autoantibodies, and 61% had serum aminotransferase levels more than five times and 46% more than ten times the upper reference range. The proportion of the different aetiological agents was different from what has been reported in other studies. The activity of the disease, judged by the serum level of aminotransferase, was more pronounced than reported in other investigations. This may indicate that only relatively severe cases of CAH were subjected to liver biopsy.