Hepatitis C virus (HCV) infections are common and can cause end-stage liver disease. The majority of infected persons are asymptomatic and unaware of their condition. The course of HCV infection in asymptomatic persons has not been clearly described. Factors that may increase the likelihood of progression to cirrhosis include (1) younger age at infection, (2) alcohol use, and (3) co-infection with hepatitis B virus or human immunodeficiency virus. Alberti and associates studied HCV infection in 4,820 otherwise healthy persons in northern Italy.

Of the 116 persons who repeatedly tested positive for anti-HCV, 85 were positive for HCV RNA. Of this latter group, 39 (46 percent) had normal serum alanine aminotransferase (ALT) levels on repeated tests for the following year, 37 (43.5 percent) had elevated ALT levels at all follow-up tests, and 9 (10.5 percent) had at least one ALT measurement above normal.

Of the 78 persons who had liver biopsies, significant fibrosis or necroinflammatory activity was found in 61 percent of patients with elevated ALT levels and 19 percent of patients with normal ALT levels. The mean and peak ALT values during the one-year follow-up period correlated with the inflammatory activity and fibrosis stage. Increasing age of persons with abnormal ALT levels correlated with increasing prevalence of significant fibrosis.

The authors conclude that a substantial proportion of otherwise healthy persons with HCV infection will develop progressive liver disease. Significant fibrosis also was found among persons with normal ALT levels, although at a lower prevalence. Screening asymptomatic patients in areas with intermediate to high prevalence of HCV infection would identify additional persons with histologically active disease who might benefit from antiviral treatment.