Antagonists of tumor necrosis factor (TNF) are effective for induction and maintenance of remission of Crohn's disease (CD) and are generally prescribed when patients do not respond to conventional, less-costly medical therapies. Early initiation of anti-TNF therapy reduced rates of surgery and dose escalation due to loss of response. However, these drugs are expensive, so studies are needed on the cost effectiveness of early initiation. We aimed to determine the cost effectiveness of initiating treatment early in the disease course (within 2 years of CD diagnosis) vs later in the disease course (more than 2 years after diagnosis).
We constructed a Markov model of a hypothetical cohort of patients with CD in Canada to simulate disease progression after initiation of infliximab or adalimumab therapy. We used published loss-of-response rates to compare the lifetime cost effectiveness of early vs late initiation of anti-TNF therapies. Transition probabilities and utilities were obtained through a literature search, and costs were obtained from the Alberta Ministry of Health. Sensitivity analysis was used to characterize uncertainty.
Early initiation of infliximab yielded an additional 0.72 quality-adjusted life-years (QALYs) and saved $50,418 compared with late initiation. Early initiation of adalimumab yielded an additional 0.54 QALYs and saved $43,969. At a willingness-to-pay threshold of $50,000, early initiations of infliximab or adalimumab therapy had a 74% chance of being cost effective compared with late initiation.
In a Markov model analysis, we found initiation of either infliximab or adalimumab within 2 years of CD diagnosis to provide significant cost savings and QALYs compared with later initiation (more than 2 years after diagnosis).