A103 EARLY INITIATION OF ANTI-TNF THERAPY IS COST-SAVING COMPARED TO LATE INITIATION FOR PATIENTS WITH CROHN’S DISEASE

Abstract

Background: Anti-TNF therapies are effective for the induction and maintenance of remission in patients with Crohn's disease (CD), and are generally prescribed when patients fail to respond to conventional, less-costly medical therapies including steroids and immunomodulators. Our recent retrospective study showed that early initiation (within two years of diagnosis) of anti-TNF therapies reduced rates of surgery and loss of response requiring dose escalation. It is hypothesized that early initiation of anti-TNF therapy may minimize chronic, irreversible changes to the bowel, such as fibrosis, stenosis, and the formation of fistula. However, the cost-effectiveness of this strategy is unknown, given the expensive nature of these medications. Aim(s): The aim of this study was to determine the cost-effectiveness of early versus late initiation of anti-TNF therapy for the management of CD. Method(s): A Markov model was constructed to simulate the progression of a hypothetical cohort of patients with CD after the initiation of either infliximab or adalimumab. Using this model, we compared the lifetime cost-effectiveness of early (2 years after diagnosis) versus late (>2 years after diagnosis) initiation of anti-TNF therapy using published loss of response rates. Transition probabilities were determined through a literature search, giving priority to randomized controlled trials with large sample sizes, followed by observational studies if needed. Health state costs were obtained from the Alberta Ministry of Health by linking inpatient, ambulatory, and physician claim databases. Utility scores were obtained from published literature using the Standard Gamble Approach. Deterministic and probabilistic sensitivity analysis was used to characterize uncertainty related to input parameters. Costs and outcomes were discounted at a rate of 5% per year. Result(s): Over a patient's lifetime, early initiation of infliximab yielded an additional 1.02 quality-adjusted life years (QALYs) and saved $18,054 compared to late initiation of infliximab. Early initiation of adalimumab yielded an additional 0.74 QALYs and saved $18,526 compared to late initiation of adalimumab. At a willingness-to-pay threshold of $50,000 per QALY, early initiation of both infliximab and adalimumab had a 68% chance of being cost-effective, while late initiation had a 32% chance of being cost-effective. Conclusion(s): Based on our current model, early initiation of either infliximab or adalimumab is cost-saving and dominates late initiation for patients with CD. Sensitivity analysis revealed these results were robust. The results of this study may serve to support early treatment with anti-TNF therapy from both a cost and patient outcome perspective.