TNF and rheumatoid arthritis: The authors concluded that the results obtained in the different clinical trials cannot necessarily be extrapolated to the routine care of patients with RA and proposed the presence of discrepancies between the results of studies that evaluated the efficacy of anti-TNF alpha drugs[31,32] and those of registry-based real-world studies.[30,33] The hypothesis underlying these differences would be that clinical trial outcomes are evaluated in highly selected populations, thus leading to an overestimation of the effect and underestimation of possible adverse events.