TNF inhibitors in the treatment of rheumatoid arthritis in clinical practice: costs and outcomes in a follow up study of patients with RA treated with etanercept or infliximab in southern Sweden

Abstract

Objectives: To evaluate costs, benefits, and cost effectiveness of tumour necrosis factor inhibitor treatment over one year in routine clinical practice.

Materials and methods: At four rheumatology units in southern Sweden treatment of 160 consecutive patients with RA was started with either etanercept or infliximab. The economic analysis was based on 116 patients with complete data who received treatment for at least one year. Details on drug treatment, functional capacity, disease activity, and laboratory values were available during the entire treatment. Information on resource use and QoL was collected at baseline and throughout the first year. The cost effectiveness analysis was based on changes in outcome and costs compared with the year before treatment. Cost per quality adjusted life year (QALY) gained was calculated for the entire sample and for patients with different levels of functional disability.

Results: During the first treatment year direct costs were reduced by 40%, but indirect costs did not change substantially. Patients' QoL improved on treatment-utility increased from an average of 0.28 to 0.65. Assuming that improvement occurred after three months' treatment, the cost per QALY gained is estimated as euro;43 500. If it occurs after six weeks, in parallel with clinical measures, the cost per QALY is euro;36 900. Sensitivity analysis, including all 160 patients, gave an estimated cost per QALY of euro;53 600. The cost per QALY increases for patient groups with less severe disease.

Conclusion: For this patient group, cost effectiveness ratios are within the generally accepted threshold of euro;50 000, but need to be confirmed with larger samples.

Figure 1

Development of functional disability (HAQ), disease activity (DAS28), and steroid use over time. The box plots represent the 10th, 25th, median, 75th, and 90th centiles.