Cost-utility of initial medical management for Crohn's disease perianal fistulae

Background & Aims: The cost-utility of infliximab is unknown. The aim of this study was to determine the incremental cost-utility (CUinc) of medical therapy for Crohn's disease (CD) perianal fistula. Methods: A Markov model was used to simulate a 1-year treatment period with the following: 6-mercaptopurine and metronidazole [6MP/met] (comparator), 3 infliximab infusions + 6MP/met as second-line therapy (intervention I), infliximab with episodic reinfusion (intervention II), and 6MP/met + infliximab as second-line therapy (intervention III). Utilities were elicited from patients with CD and healthy individuals by standard gamble, and costs were obtained from hospital billing data. Uncertainty was assessed by sensitivity analysis. Results: All strategies had similar effectiveness. Interventions I, II, and III were slightly more effective, but also more costly than 6MP/met (Intervention I: CUinc = $355,450/quality-adjusted life-years [QALY]; Intervention II: CUinc = $360,900/QALY; Intervention III: CUinc = $377,000/QALY). If the cost of infliximab were reduced to $304 per infusion, the CUinc for intervention II would be $54,050/QALY. Conclusions: Based on available data, all strategies had similar effectiveness in our model, but infliximab was much more expensive than 6MP/met. The incremental benefit of infliximab for treating CD perianal fistulae over a 1-year period may not justify the higher cost. Prospective studies directly comparing 6MP/met and infliximab are warranted.