Incidence rates and causes of cirrhosis in a Norwegian population

Objective. To investigate the incidence rate and causes of cirrhosis in a Norwegian population. We also sought to assess the degree of underreporting of cirrhosis to the Norwegian Death Registry. Material and methods. All 1264 patients treated at Aker University Hospital in the period January 1999 to March 2004 who were given a diagnosis indicating cirrhosis, chronic liver disease or symptoms possibly attributable to cirrhosis were screened retrospectively. A search of the registry of histological diagnoses at Department of Pathology was also carried out. Based on the results of histological examinations and non-histological criteria, cirrhosis was confirmed in 194 patients. Calculations of the incidence rate of cirrhosis and frequencies of the various etiologies were based on 93 patients living in the catchment area of the hospital. Causes of death were retrieved from the Norwegian Death Registry. Results. The incidence rate of cirrhosis was 134 per million per year. The majority of cases were due to alcoholic liver disease (53%), followed by viral liver disease (12%), various autoimmune liver diseases (12%), hemochromatosis (4%) and non-alcoholic steatohepatitis (NASH) (3%). No etiology was established in 16%, a group with a high prevalence of diabetes mellitus, indicating that some of these cases were possibly caused by NASH. Among 105 deaths in this cohort of 194 cirrhotic patients, the diagnosis of cirrhosis was absent in the Norwegian Death Registry in 30% of cases. Conclusions. The incidence of cirrhosis in Norway is relatively low, with alcohol as the most important etiologic factor. Significant underreporting to the Norwegian Death Registry was observed.