Brandon TG, Xiao R, Peterson RG, et al. - Analyzing changes in magnetic resonance imaging (MRI) lesions in the sacroiliac joint (SIJ) under different treatment conditions, a greater improvement was evident on follow-up imaging in tumor necrosis factor inhibitor (TNFi) exposed children with spondyloarthritis (SpA) vs the unexposed group by most metrics, some of which reached statistical significance.

• In this retrospective, multicenter study, a total of 46 SpA patients with suspected or confirmed sacroiliitis who had at ≥2 pelvic MRI scans were included.

• Of participants, 23 (50%) were TNFi exposed, and images were scored using the Spondyloarthritis Research Consortium of Canada (SPARCC) SIJ inflammation score (SIS) and structural score (SSS).

• In TNFi exposed and unexposed cases, median change in SIS from a baseline SIS ≥0 was − 20.7 and − 14.3, respectively.

• The SIS minimal clinically important difference (MCID; ≥2.5) was met by 85% TNFi exposed and 89% unexposed patients with a baseline SIS ≥0.

• Employing the average treatment effects model adjusted for baseline SIS, TNFi was shown to exert an average effect of − 14.5 on SIS in patients with a baseline SIS ≥2.

• Surprisingly, the SIS MCID was met by a majority of TNFi unexposed children with a baseline SIS≥2.