Not all “quality-adjusted life years” are equal

• Published in: Journal of clinical epidemiology Vol. 60; no. 6; pp. 616 - 624
• Main Authors: Marra, C.A, Marion, S.A, Guh, D.P, Najafzadeh, M, Wolfe, F, Esdaile, J.M, Clarke, A.E, Gignac, M.A, Anis, A.H
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-06-2007; Elsevier; Elsevier Limited
• Subjects: Antibodies, Monoclonal - economics; Antibodies, Monoclonal - therapeutic use; Antirheumatic Agents - economics; Antirheumatic Agents - therapeutic use; Arthritis, Rheumatoid - economics; Arthritis, Rheumatoid - rehabilitation; Biological and medical sciences; Cost-Benefit Analysis; Cost-effectiveness; Data Interpretation, Statistical; Diseases of the osteoarticular system; Drug therapy; Drug Therapy, Combination; Economic evaluation; Epidemiology; General aspects; Humans; Inflammatory joint diseases; Infliximab; Internal Medicine; Markov Chains; Medical sciences; Methodology; Methods; Methotrexate - economics; Methotrexate - therapeutic use; Models, Statistical; Mortality; Public health. Hygiene; Public health. Hygiene-occupational medicine; Quality of life; Quality-Adjusted Life Years; Rheumatoid arthritis; Studies; Survival Analysis; Time Factors; Utility values; Quality-adjusted life years; Cost-effectiveness; Rheumatoid arthritis; Utility values; Methods; Economic evaluation; Antineoplastic agent; Costs; Methodology; Diseases of the osteoarticular system; Autoimmune disease; Inflammatory joint disease; Index; Monoclonal antibody; Epidemiology; Antifolate; Infliximab; Anticytokine; Methotrexate; Willingness to pay; Tumor necrosis factor α; Public health; Cost efficiency analysis; Human; Immunopathology; Use; Cytokine; Patient; Mathematical method; Quality of life; Immunomodulator; Chronic; Antimetabolic; Simulation; Health economy; Economic aspect; Immunosuppressive agent; Economic impact; Measurement method; Comparative study
• ISSN: 0895-4356; 1878-5921
• DOI: 10.1016/j.jclinepi.2006.09.006

Abstract Background There is evidence that utility elicitation methods used in the calculation of quality-adjusted life years (QALYs) yield different results. It is not clear how these differences impact economic evaluations. Methods Using a mathematical model incorporating data on efficacy, costs, and utility values, we simulated the experiences of 100,000 hypothetical rheumatoid arthritis patients over 10 years (50,000 exposed to infliximab plus methotrexate [MTX] and 50,000 exposed to MTX alone). QALYs, were derived from the Health Utilities Index 2 and 3 (HUI2 and HUI3), the Short Form 6-D (SF-6D), and the Euroqol 5-D (EQ-5D). Incremental cost-utility ratios were determined using each instrument to calculate QALYs and the results were compared using cost-effectiveness acceptability curves. Results Using the different utility measurement methods, the mean difference in QALYs between the infliximab plus MTX and MTX groups ranged from a high of 1.95 QALYs (95% CI = 1.93–1.97) using the HUI3 to 0.89 QALYs (95% CI = 0.88–0.91) using the SF-6D. Adopting the commonly cited value of society's willingness to pay for a QALY of $50,000, 91% of the simulations favored the cost utility of infliximab plus MTX when using the HUI3 to calculate QALYs. However, when using the EQ-5D, HUI2, or the SF-6D utility values to calculate QALYS, the proportion of simulations that favored the cost utility of infliximab were 63%, 45%, and 12%, respectively. Conclusion Depending on the method for determining utility values used in the calculation of QALYs, very different incremental cost-utility ratios are generated.