LEP and rheumatoid arthritis: A previous study within the same cohort, which evaluated the possible clinical association of treatment response in RA patients with levels of leptin or adiponectin, as well as overweight and obesity showed an association of circulating leptin and clinical activity (Xibille‐Friedmann et al., 2015), but that was not the case in the present study because differences in the body mass index between patients did not change the association values of PD or oral PAD activity (data not shown).