Modeling the impact of interferon alfa treatment on liver fibrosis progression in chronic hepatitis C: A dynamic view

Background & Aims: Impact of hepatitis C treatment has never taken into acc ount the dynamics of fibrosis progression. This study assessed the impact o f interferon on liver fibrosis progression in patients with chronic hepatit is C according to 3-month aminotransferase activity response. Methods: We r ecruited 287 patients, 185 treated and 102 control, with paired biopsy spec imens. Before follow-up, the fibrosis progression rate per year was estimat ed as the ratio between fibrosis stage in METAVIR units (1 U, 1 stage; 4 U, cirrhosis) and the duration of infection. During follow-up, fibrosis progr ession was assessed by the observed difference between stages divided by du ration between biopsies. Results: The median fibrosis progression rate in t reated patients decreased compared with the rate before treatment from 0.10 3 F METAVIR U/yr (95% confidence interval [CI], 0.087-0.120) to 0.000 (95% CI, 0.000-0.000; P less than or equal to 0.0001). Among 91 treated responde rs, fibrosis stage worsened in 19 (22%), compared with 21 (22%) of 94 treat ed nonresponders and 51 of 102 controls (56%; P less than or equal to 0.000 1 compared with treated patients), and improved in 26 (29%), 17 (18%), and 8 (8%; P = 0.0002 compared with 29% and P = 0.03 compared with 18%), respec tively. These observed differences persisted after genotype, viremia, sex, age at infection, duration of infection, and alcohol consumption were taken into account. Conclusions: Interferon treatment changes the natural fibros is progression rate in patients with chronic hepatitis C independently of g enotype and early response.