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) naive 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 pound higher total medical costs. The ICER was 18 pound 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.