Prolonged treatment with interferon in patients with histologically mild chronic hepatitis C: a decision analysis

Short courses (6 months) of interferon (IFN) are highly cost-effective in patients with histologically mild chronic hepatitis C. However, IFN treatment lasting 12-24 months is now the standard of care. We utilized a previously published and validated model of the natural history of chronic hepatitis C and the treatment outcomes from two large multicentre treatment trials of IFN-alpha 2b, given for 6 months or 18-24 months, to estimate the incremental cost-effectiveness of prolonged IFN treatment in patients with histologically mild chronic hepatitis C (formerly chronic persistent or mild chronic active hepatitis). In the two treatment trials, pooled analysis of the patients with mild hepatitis showed that 36.4% of them normalized serum alanine aminotransferase and remained virus negative (sustained response) after completing an 18-24 month course of IFN vs 15.3% for a 6-month course and no response in the absence of treatment. The model then estimated that for patients aged 20-50 years, the discounted marginal cost per year of life gained by long-term IFN treatment ranged from US $735 to US $8856, and the gain in life expectancy ranged from 4.35 years to 0.75 years, respectively, compared with an untreated age-matched cohort. Compared with treatment for only 6 months, the incremental marginal cost per life year gained by longer treatment at age 20-50 years ranged from $938 to $9957. The treatment and healthcare costs, sustained response rates and the rate of progression during early disease were identified as significant variables in sensitivity analyses. However, longer treatment always showed a survival benefit compared with 6 months of IFN or no treatment, and the cost of longer treatment is reasonable compared with that for a 6-month course.