Tight control for Crohn's disease with adalimumab-based treatment is cost-effective: an economic assessment of the CALM trial

Objective: To evaluate the cost-effectiveness of an inflammatory biomarker and clinical symptom directed tight control strategy (TC) compared with symptom-based clinical management (CM) in patients with Crohn's disease (CD) naïve to immunosuppressants and biologics using a UK public payer perspective.

Design: A regression model estimated weekly CD Activity Index (CDAI)-based transition matrices (remission: CDAI <150, moderate: CDAI ≥150 to <300, severe: CDAI ≥300 to <450, very severe: CDAI ≥450) based on the Effect of Tight Control Management on Crohn's Disease (CALM) trial. A regression predicted hospitalisations. Health utilities and costs were applied to health states. Work productivity was monetised and included in sensitivity analyses. Remission rate, CD-related hospitalisations, adalimumab injections, other direct medical costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratio (ICER) were calculated.

Results: Over 48 weeks, TC was associated with a higher clinical remission (CDAI <150) rate (58.2% vs 46.8%), fewer CD-related hospitalisations (0.124 vs 0.297 events per patient) and more injections of adalimumab (40 mg sc) (mean 31.0 vs 24.7) than CM. TC was associated with 0.032 higher QALYs and £593 higher total medical costs. The ICER was £18 656 per QALY. The ICER was cost-effective in 57.9% of simulations. TC became dominant, meaning less costly but more effective, when work productivity was included.

Conclusion: A TC strategy as used in the CALM trial is cost-effective compared with CM. Incorporating costs related to work productivity increases the economic value of TC. Cross-national inferences from this analysis should be made with caution given differences in healthcare systems.

Trial registration number: NCT01235689; Results.