Study population
One hundred thirty-seven patients (37 with RA, 53 with SpA and 47 with CD) treated by TNF alpha blockers (IFX=68, ADA=69) were included in the study. All patients fulfilled the ACR/EULAR 2010 criteria for RA [6], the Assessment of Spondyloarthritis international Society (ASAS) 2010 criteria for SpA [7] or the 2006 Montreal classification for CD [8]. All included patients had to be TNF alpha blockers naïve, and had to receive the current biologic for at least 6 months.