[Use and cost of biological disease-modifying anti-rheumatic drugs in Spain (PRAXIS study)].

OBJECTIVE To analyse the use of health care resources and the associated costs in patients with rheumatoid arthritis (RA) treated with three biological disease-modifying anti-rheumatic drugs (bDMARDs): etanercept, infliximab and adalimumab. METHOD DESIGN observational, retrospective, multicentre study. Length of study: 6 months. TARGET POPULATION patients with RA, who have been undergoing treatment for at least one year. SCOPE Spanish National Health System hospitals. Use of resources: review of the patient records of all patients included in the study by the Hospital Pharmacy Departments. Health care costs: the unit costs were obtained from Spanish databases; disease costs per patient were estimated from the use of resources results (euro in July 2006). Sensitivity analysis: univariate of base case. Budget impact analysis: replacement of infliximab and adalimumab by etanercept for three hospital populations. RESULTS 1,111 patient records from 41 Spanish hospitals were reviewed, 432 patients were treated with etanercept, 396 were treated with infliximab and 283 with adalimumab. Mean doses: etanercept: 48.90 mg per week; infliximab: 4.14 mg/kg every 8 weeks; adalimumab: 41.58 mg every two weeks (97.8, 138 and 104% respectively, of recommended doses). Treatment with etanercept led to fewer costs. Compared to infliximab, six-monthly costs per patient were reduced with etanercept as follows: bDMARD treatment (232.23 euro), treatment failure (163.42 euro), consultations (54.88 euro), tests (22.52 euro) and costs associated to bDMARD administration (euro 474.42). The saving per patient treated with etanercept compared to infliximab for six months was 577.94 euro. With respect to adalimumab, the savings with etanercept were mainly related to bDMARDs (1,111.74 euro) and test costs (10.16 euro), obtaining a six-monthly saving of euro 906.68 per patient treated with etanercept. Sensitivity analysis confirmed the robustness of the base case in the majority of cases, with six-monthly savings of 395.79-644.32 euro per patient compared to infliximab and of 672.09-1.159.46 euro compared to adalimumab. Infliximab treatment was less expensive than etanercept and adalimumab treatment when taking into consideration the minimum possible number of doses of infliximab (3 doses for six months). Hospital budget savings could be obtained as a consequence of a reduction in costs due to use of etanercept, ranging from 14,500-231,100 euro when replacing infliximab with etanercept and from 22,600-362,600 euro when replacing adalimumab with etanercept, according to the hospital population included (50 to 200 patients). CONCLUSIONS Our results showed that in most cases, the treatment of rheumatoid arthritis with etanercept compared to infliximab and adalimumab reduced hospital costs.