Hepatitis activity index is a key factor in determining the natural history of chronic hepatitis C.

To analyze the spontaneous pathologic progression of chronic hepatitis C, we analyzed the histopathologic semiquantitative scores (Metavir and Knodell) of sequential liver biopsies performed in untreated hepatitis C virus (HCV)-infected patients. Subjects included 35 men and 41 women, with a mean age of 41 +/- 12 years, a duration of HCV infection of 11 +/- 5 years, and an interval between liver biopsies of 3.7 +/- 2.5 years. Results obtained using the Knodell score and the Metavir score were similar. At the first biopsy, 78.9% of patients had a low activity score (A0-A1) and 82.9% had a low fibrosis score (F0-F2). At the second biopsy, the activity decreased in 9.2%, was unchanged in 72.4%, and increased in 18.5%. An increase in activity was more frequently observed in patients infected with genotype 1 (28.9%) than with others (7.7%; P =.04); the yearly progression of activity was significantly higher in patients with a low rather than high initial activity score (0.11 v -0.02; P <.01). An increase in fibrosis was noted in 13.3% of those with a low and 43.8% of those with a high initial activity score (P <.01), with a highest rate of yearly fibrosis progression (0.12 U). In multivariate analysis, only a high activity score was significantly associated with an increased risk of fibrosis progression (relative risk, 25.5; 95% confidence interval, 2.7 to 238; P =.004). Spontaneous chronic hepatitis C evolution is worsening in only 20% of patients. Fibrosis progression is significantly associated with the necroinflammatory activity suggesting that this factor should be regarded as a major clue for deciding therapy. Copyright 2001 by W.B. Saunders Company