Cost effectiveness of combination therapy for hepatitis C: a decision analytic model

Abstract
Objective: To estimate the cost utility of treatment with combination therapy (ribavirin and interferon α) for hepatitis C compared with no treatment or monotherapy (interferon α) based on UK costs and clinical management. Design: Decision analysis model using a Markov approach to simulate disease progression. Setting: UK secondary care. Participants: Hypothetical cohort of patients with hepatitis C. Main outcome measures: Cost per quality adjusted life year (QALY) gained. Results: Discounted cost per QALY for combination therapy over no treatment was £3791. Cost per QALY varied between £1646 and £9170 according to subgroup, with the lowest ratios being for genotype 2 or 3, women, those aged less than 40 years, and those with moderate hepatitis. The discounted cost per QALY of the combination over monotherapy was £3485. Similar findings were shown for subgroups as for the comparison with no treatment. One way sensitivity analysis showed that while drug costs were more important in the analysis than assumptions about disease progression or costs of treating hepatitis C disease, the results were robust to large changes in underlying assumptions. Conclusions: Combination therapy for hepatitis C is a cost effective treatment option and is superior to monotherapy. Considerable uncertainties remain over the appropriate management strategies in the populations excluded from randomised controlled trials and in whom treatment is currently being considered in the UK.