Rheumatoid arthritis is one of the most frequent auto-immune diseases, with a prevalence of around 0.5 % of the population. Untreated, it can lead to severe joint damage, loss of function and decreased quality of life. Several options are available to treat rheumatoid arthritis, starting with conventional treatment (e.g. methotrexate, leflunomide, …). Many second-line treatments have been developed to treat rheumatoid arthritis that can be used after the failure of the conventional treatments. They have all been evaluated to show their efficacy in head-to-head randomised controlled trials against placebo, first-line therapies, and less frequently, against another second-line therapy. However, randomised controlled trials are not representative of the real-world population with as much as 80% of rheumatoid arthritis patients who could not be enrolled in trials because of the selection criteria. Observational studies are thus essential to evaluate the effect of treatment in the real world clinical practice. Additionally, they allow the comparison of several alternative treatments against each-other and their long-term evaluation.

This first study assesses the quality of the current landscape of observational studies comparing the effectiveness of rheumatology treatments, showing that there is leeway for improvement in methodology, particularly in the handling of missing data, loss of follow-up and confounding. Then, two other studies evaluate the real-world effectiveness of one of the most recent biologics developed for RA, tocilizumab, one in patients who already experienced a previous second-line therapy and the other in so-called ‘bionaïve’ patients, demonstrating that tocilizumab is more effective than TNF-inhibitors when given as monotherapy (meaning without methotrexate or another conventional treatment), and thus a better treatment option when co-therapy with a conventional treatment, which is the usual standard of treatment, is not possible or desired. Finally, the last study shows that Janus-kinases inhibitors, the latest treatment-class available for RA, are as effective as most of the current treatment options for rheumatoid arthritis, and the choice of a second-line therapy must then be made on other aspects than effectiveness, such as safety, costs and patient preferences.