Analytical approach:
The analysis was based on a Markov model, with a lifetime horizon. The authors stated that the perspective of private medicine was adopted and this included insurers, health maintenance organisations, cooperatives, and self-management organisations.
Effectiveness data:
The clinical data came from the published literature and Brazilian population statistics. Three observational studies were used to derive the transition probabilities for the natural histories of mild and moderate chronic hepatitis C. The treatment effect for pegylated interferon plus ribavirin was from a single randomised controlled trial, while the effect for interferon plus ribavirin was from other studies. Mortality was based on Brazilian life tables. The key endpoint was the rate of sustained viral response, which was defined as the absence of serum hepatitis C virus ribonucleic acid at the end of treatment and six months later.
Monetary benefit and utility valuations:
The utility values for each health state were from two published studies and were assumed to be the same for the two treatment arms. In these two studies, the utilities were established by a panel of hepatologists.
Measure of benefit:
Quality-adjusted life-years (QALYs) were the summary benefit measure and were discounted at an annual rate of 3%.
Cost data:
The economic analysis included the costs of the two drug regimens and the long-term treatment of chronic hepatitis C, which was micro-costed by modified Delphi panels of six hepatologists, six oncologists, and six intensive care physicians. The unit costs were based on public prices for all items. The costs were presented as category totals for health conditions. They were in Brazilian reais (BRL) and were discounted at a rate of 3% per annum. The price year was 2006.
Analysis of uncertainty:
One- and two-way sensitivity analyses were carried out on most of the clinical and economic inputs, using plausible published ranges of values. A Monte Carlo simulation was carried out.
