Two-year cost-effectiveness of different COBRA-like intensive remission induction schemes in early rheumatoid arthritis: a piggyback study on the pragmatic randomised controlled CareRA trial

Objectives To evaluate the cost-effectiveness of treat-to-target strategies among recently diagnosed patients with rheumatoid arthritis (RA) using methotrexate (MTX) and a step-down glucocorticoid (GC) scheme (COBRA Slim) compared with (1) this combination with either sulphasalazine (COBRA Classic) or leflunomide (COBRA Avant-G arde) in high-risk patients and (2) MTX without GCs (Tight-S tep-Up, TSU) in low-risk patients.

Methods The incremental cost-utility was calculated from a healthcare perspective in the intention-to-treat population (n=379) of the 2-year open-label pragmatic randomised controlled Care in early RA trial. Healthcare costs were collected prospectively through electronic trial records. Quality-adjusted life years (QALYs) were estimated using mapping algorithms for EuroQoL-5 Dimension. Multiple imputation was used to handle missing data and bootstrapping to calculate CIs. Robustness was tested with biological disease-modifying antirheumatic drugs at biosimilar prices.

Results In the high-risk group, Classic (Delta k(sic)1.464, 95%CI -0.198 to 3.127) and Avant-G arde (Delta k(sic)0.636, 95%CI -0.987 to 2.258) were more expensive compared with Slim and QALYs were slightly worse for Classic (Delta-0.002, 95%CI -0.086 to 0.082) and Avant-Garde (Delta-0.009, 95%CI -0.102 to 0.084). This resulted in the domination of Classic and Avant-G arde by Slim. In the low-risk group, Slim was cheaper (Delta k(sic)-0.617, 95%CI -2.799 to 1.566) and QALYs were higher (Delta 0.141, 95%CI 0.008 to 0.274) compared with TSU, indicating Slim dominated. Results were robust against the price of biosimilars.

Conclusions The combination of MTX with a GC bridging scheme is less expensive with comparable health utility than more intensive step-down combination strategies or a conventional step-up approach 2 years after initial treatment.