The costs and benefits were combined by calculating a cost-effectiveness ratio (the average cost per patient with successful therapy response at year 4) and an incremental cost-effectiveness ratio (ICER; the cost per additional patient responding to adefovir dipivoxil). The ICER is the important statistic.
The cost-effectiveness ratio was EUR 28,375 for the lamivudine arm and EUR 28,132 for the adefovir dipivoxil arm.
The ICER of adefovir dipivoxil versus lamivudine was EUR 27,872.
The sensitivity analysis found that only two variables significantly impacted on the results. These were the virological response rate to adefovir dipivoxil and the virological response rate to lamivudine. If the proportion of the lamivudine arm responding at year 4 increased to above 40.7%, there was a favourable impact on the average cost-effectiveness analysis for the lamivudine strategy.