Assessing the cost-effectiveness of tumor necrosis factor inhibitors and prescribing practices of rheumatologists in patients with rheumatoid arthritis

Abstract

Three new tumor necrosis factor (TNF) inhibitors, adalimumab, etanercept, and infliximab, have been approved for use in patients with active RA. The goals of the study were two fold: 1) to perform a cost-effectiveness analysis of the three TNF inhibitors in patients with RA that inadequately respond to MTX alone and 2) to assess the current prescribing patterns, laboratory monitoring practices, and perceived barriers of rheumatologists in prescribing these agents in patients with RA. Phase I involved the development of a Markov simulation model to estimate the health effects and costs associated with five treatment strategies in patients with RA that inadequately respond to MTX alone: (1) adalimumab plus MTX, (2) etanercept plus MTX, (3) infliximab plus MTX, (4) leflunomide plus MTX, and (5) standard therapy of MTX. A hypothetical cohort of 10,000 55-year old women was evaluated using Monte Carlo simulation. The study was conducted from a societal perspective. The main outcome measures were net gains in quality-adjusted life expectancy and incremental costeffectiveness ratios, (ICERs) in dollars per quality adjusted life year (QALY) gained. Costs and effects were discounted at 3%. Etanercept plus MTX was the most costeffective treatment with an ICER of $49,724/QALY. Leflunomide plus MTX was the second most cost-effective option with an ICER of $52,833/QALY. One-way and probabilistic sensitivity analyses indicated that the conclusions were relatively stable to variations in model assumptions. In phase II, a survey was mailed to a randomly selected national sample of rheumatologists, of which 22.3% responded. The survey findings indicated that TNF inhibitor use was not restricted to moderate and severe patients with RA. Also, TNF inhibitor plus one disease modifying anti-rheumatic drug was the treatment of choice in patients with severe RA that inadequately respond to MTX alone. Costs to the patient and insurance coverage were perceived as major barriers in prescribing TNF inhibitors. One-fourth of the rheumatologists reported not using any monitoring guidelines for the TNF inhibitors indicating a need to revise monitoring guidelines or perhaps implement new guidelines for TNF inhibitors. ACKNOWLEDGEMENT First and foremost, I would like to thank my advisor and Committee Chairperson Dr. Suresh Madhavan for his guidance, encouragement, and constant support throughout my dissertation and graduate studies. His patience and never wavering good nature always eased the frustration that was encountered over the years.