Introduction: Recent guidelines propose a fecal calprotectin (FCP) monitoring strategy in the year after Crohn’s disease (CD) resection for low-risk individuals or those receiving pharmacologic prophylaxis to prevent postoperative recurrence (POR). We aimed to explore the cost effectiveness of FCP compared to endoscopic monitoring strategies in postoperative CD.

Methods: We employed Markov simulation modeling to determine the cost-effectiveness of FCP compared to ileocolonoscopy in monitoring for POR of CD following ICR. The baseline case was a biologic naïve 35-yo male with a history of stricturing ileal CD who undergoes ICR without postoperative prophylaxis and surgically induced remission. In the 6-mo following ICR, individuals could develop symptoms prompting an ileocolonoscopy to assess for POR followed by initiation of biologic therapy, modeled with adalimumab (ADA), or they would remain asymptomatic, undergoing either an ileocolonoscopy or FCP at 6 months (Figure 1). POR found during an asymptomatic disease assessment would prompt ADA initiation and ileocolonoscopy 6 months later. Those with persistent disease on ADA transitioned to ustekinumab (UST). A FCP of <50 ug/g at 6 months was used as a cutoff to rule out POR. The potential for a false negative FCP, and ensuing increased risk of flare, was also simulated. A FCP ≥50 ug/g would prompt endoscopic assessment. All individuals were exposed to a continuous risk of symptomatic flare. The time horizon was 18 months. Transition probabilities were derived from published meta-analyses, controlled trials, and observational studies. Costs were derived from the Nationwide Inpatient Sample, Medicare reimbursement rates and wholesale acquisition costs. Primary analyses for mean costs, quality-adjusted life year(QALY) estimates, mean incremental cost effectiveness ratios, and net monetary benefits were conducted using first-order Monte Carlo simulation of 100 trials of 100,000 in individuals. All models assumed a willingness to pay threshold of $50,000 per QALY gained.

Results: In first order Monte Carlo analysis, the FCP strategy to monitor for POR of CD resulted in a $46,859.92 reduction in cost compared to endoscopic assessment (Table 1). Effectiveness was similar, with an incremental effectiveness of 0.008 in favor of the FCP strategy. Thus, the FCP strategy strongly dominated the ileocolonoscopy strategy over 18 months. Using a FCP monitoring strategy resulted in a 52.9% reduction in the number of colonoscopies performed, a 42% reduction in the number ADA initiations, and a 44% reduction in the number of UST initiations compared to the endoscopic assessment strategy.

Discussion: FCP-based monitoring of POR of biologic naïve CD the first year after surgery appears to be cost-effective compared to endoscopic assessment. The longer-term implications regarding this approach require further study.

Table 1 Caption: Results of cost-effectiveness analysis for each strategy and overall ICERs at 18 months for the base model. *Results for strongly dominated strategies and negative ICER calculations are not reported.
Abbreviations: FCP: Fecal calprotectin, ICER: Incremental cost-effectiveness ratio, QALY: Quality-adjusted life year, NMB: Net Monetary Benefit, ADA: Adalimumab, UST: Ustekinumab

Terry Li

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