Background and importance Immune-mediated inflammatory diseases (IMIDs) present a high burden of illness, as they are chronic conditions with associated comorbidities and high indirect costs. In Spain, IMIDs prevalence is around 6% and rheumatoid arthritis (RA) (1%) is one of the most common among them. The introduction of biological treatments, like adalimumab (ADA), has contributed to improve RA’s clinical outcomes. The high cost of these biologics used to be a hurdle for their prescription until the appearance of biosimilars. Cost-effectiveness analysis can help in decision-making for this pathology.

Aim and objectives Our objective was to assess the cost-effectiveness of ADA and its clinical alternatives in RA.

Material and methods We built a cost-effectiveness model based on meta-analyses (direct or indirect) conducted between 2015 and 2021. We gathered all the effectiveness information (American College of Rheumatology (ACR)) through a PICO-S strategy including infliximab, etanercept, certolizumab, tocilizumab, golimumab, tofacitinib and upadacitinib. Two reviewers evaluated the inclusion of the studies and assessed their quality using the PRISMA-NMA Checklist. Efficiency score was cost per number needed to treat (NNT) versus placebo (PLC). The model was designed from a hospital perspective (only direct costs) and with a 1-year horizon. Cost data (€2021) were obtained from Spanish datasets and literature review. Using all this information, a cost-effectiveness analysis between ADA and the suitable alternatives was performed. A probabilistic sensitivity analysis (PSA) was performed.

Results Two meta-analyses met the inclusion criteria and fulfilled on average 70.6% of the 32 points on the PRISMA-NMA Checklist of items. Tarp et al (2017) showed no statistically significant difference in NNT between infliximab, ADA, etanercept, certolizumab, tocilizumab and golimumab for ACR-50. Song et al (2019) showed no significant difference in NNT between ADA, tofacitinib and upadacitinib for ACR-20.

Total annual cost was €4529 ADA versus €4650–€10 001 for the other treatments. As no effectiveness difference was seen, a cost minimisation analysis was performed. Hence ADA was the most cost-effective treatment. In the PSA, only ADA and infliximab performed as the best alternative, with ADA showing the highest probability of being cost-effective.

Conclusion and relevance According to our model, ADA was the most cost-effective option for RA treatment in Spain.

Conflict of interest Corporate sponsored research or other substantive relationships: Axentiva Solutions recieved fees from Fresenius Kabi España, S.A.U.