Objectives. To perform, in real conditions of prescription, the medico-economic evaluation of infliximab in severe RA. Methods. A cost-effectiveness analysis of the annual costs was done with a comparison between the previous and the following year under infliximab. The effectiveness, determined from the HAQ, was expressed in clinically significant units and in quality-adjusted life years (QALYs). The incremental net benefit (INB), defined as willingness to pay (λ), was used to express the results. Results. A cohort of 635 patients was formed. Before the use of infliximab, after 1 and 2 years, the mean annual cost per patient for the care of RA was €9832, 27 723 and 46 704, respectively. Among the direct costs, infliximab accounts for €21 182 for the first year. The distribution of the different costs was similar after 2 years. By using the INB, the difference before and after 1 year under infliximab is significant, on average by 1.86 (s.e.m. = 0.76) when the effectiveness is expressed in clinically significant units. For severe HAQ, λ is €9841 (18 593 for all HAQ). When it is expressed in QALYs, also for severe HAQ, λ >€100 000. This can be explained by a short follow-up although severe complication of RA appears later. Conclusion. An evaluation of the more long-term costs is required in order to determine whether there are any full economic benefits with this treatmen
