Analytic Choices in Economic Models of Treatments for Rheumatoid Arthritis: What Makes a Difference?

Objectives. To compare the analytic judgments, data, and assumptions of different models used in the economic evalu-ation of infliximab, one of a new class of drugs for rheuma-toid arthritis (RA). Methods. A detailed assessment was made of 4 models, 1 submitted (in a reimbursement dossier) by the manufacturer, 1 produced by an independent aca-demic group, and 2 recently published in the literature. Fac-tors considered included the key data inputs, assumptions about the sequencing of treatments for RA, the methods used to calculate health utilities, and the estimation of cost offsets. Results. Two of the 4 models, although embodying different methodological approaches, gave fairly similar results (ap-proximately £25,000–£35,000 cost per additional quality-adjusted life year [QALY] gained). The other 2 models, both by an independent academic group, gave much highe