Risk factors and predictors of outcome in an Australian cohort with hepatitis C virus infection.

OBJECTIVES: To define demographic and epidemiological features of an Australian population with chronic hepatitis C virus (HCV) infection and determine predictors of histological and clinical outcome. DESIGN: Cohort study. PATIENTS AND SETTING: 342 consecutive HCV antibody-positive patients referred to the liver clinic of a major metropolitan general hospital. OUTCOME MEASURES: Demographic data, serial alanine aminotransferase (ALT) levels, full blood count for all patients. Percutaneous liver biopsy in 152 patients (44%). RESULTS: 51% of patients had previously used injecting drugs, 15% had received a blood transfusion and 27% had no definite percutaneous risk factor (sporadic group). The injecting drug users (IDUs) were younger and more likely to have been born in Australia. The sporadic group were older and frequently were born in Mediterranean or Asian countries. A history of excessive alcohol use was common, particularly among IDUs (60%). Of 152 patients who had a liver biopsy, 49 had cirrhosis and 103 had chronic hepatitis. Some patients with a normal ALT level had marked necro-inflammatory activity. On univariate analysis, the presence of cirrhosis correlated with older age (P < 0.0001), lack of an identifiable risk factor (P < 0.001) and birth in a Mediterranean or Asian country (P < 0.0001). On multivariate analysis, the only significant predictor of cirrhosis was age (P < 0.001). Among patients with an identifiable percutaneous risk factor, cirrhosis was seen at a median time of 18 years after first exposure to risk, compared with 13 years in patients with chronic hepatitis (P < 0.01). Patients with clinical evidence of portal hypertension were, on average, 15 years older than those with histological cirrhosis only (P < 0.01). CONCLUSIONS: Injecting drug use is the major risk factor for chronic HCV infection in Australia. In patients with an identifiable risk factor, the most significant factor associated with a biopsy finding of cirrhosis is the time since first exposure to HCV.