THE ECONOMIC BURDEN OF BIOLOGICAL THERAPY IN RHEUMATOID ARTHRITIS IN CLINICAL PRACTICE: COST-EFFECTIVENESS ANALYSIS OF SUB-CUTANEOUS ANTI-TNFα TREATMENT IN ITALIAN PATIENTS

Rheumatoid arthritis (RA), with a prevalence of 0.46%, is found in about 272,004 patients in Italy. The socioeconomic cost of rheumatoid arthritis in Italy in 2002 has been estimated at (sic)1,600 million. Cost-effectiveness evaluations have been based on the concept that, with treatment, patients will not progress to the next level(s) of disease severity or will take a longer time to progress, thus avoiding or delaying the high costs and low utility associated with more severe disease. Many cost-effective studies have been based on the variation of Health Assessment Questionnaire (HAQ) in clinical trials. The objective of this study is to perform a cost-effective analysis of 86 patients with rheumatoid arthritis in therapy with adalimumab 40 mg every other week and etanercept 50 mg/week for two years in a population of patients observed in clinical practice. The group of patients in therapy with adalimumab had also taken methotrexate, mean dose 12.4 +/- 2.5 mg/week (22 patients) or leflunomide 20 mg/day (16 patients). The group of patients in therapy with etanercept had also taken methotrexate, mean dose 11.7 +/- 2.6 mg/week (24 patients) or leflunomide 20 mg/day (24 patients). Incremental costs and QALYs (quality adjusted life years) gains are calculated compared with baseline, assuming that without biologic treatment patients would remain at the baseline level through the year. Conversion HAQ scores to utility were based on the Bansback algorithm. The results after two years showed: in the group methotrexate+adalimumab the QALY gained was 0.62 +/- 0.15 with a treatment cost of (sic)26,517.62 and a QALY/cost of (sic)42,521.13. In the group methotrexate+etanercept the QALY gained was 0.64 +/- 0.26 with a treatment cost of (sic)25,020.96 and a QALY/cost of (sic)39,171.76. The result of using etanercept in association with methotrexate is cost-effectiveness with a QALY gained under the acceptable threshold of (sic)50,000. These are important data for discussion from an economic point of view when we choose a biologic therapy for rheumatoid arthritis in clinical practice.