How Common Is Sacroiliac Joint Damage in Patients With Nonradiographic Axial Spondyloarthritis?

With the exception of erosion, patients with radiographic axial spondyloarthritis (r-axSpA) had more active inflammatory and chronic structural damage of the sacroiliac joint than patients with nonradiographic axial spondyloarthritis (nr-axSpA), according to a study published online in Frontiers in Immunology.

“The results of this study demonstrate that structural lesions on magnetic resonance imaging (MRI) may occur in early stage of spondyloarthritis (nr-axSpA) and in the absence of sacroiliac joint bone marrow edema on MRI. R-axSpA patients have more sacroiliac joint inflammation on MRI, and fat metaplasia is seen more in r-axSpA than nr-axSpA patients,” reported researchers from Sun Yat-Sen University in China. “Our data also support that structural damages in sacroiliac joint are associated with active inflammation.”

The findings are based on MRI scans of the sacroiliac joint in 253 patients.

Spondyloarthritis Research Consortium of Canada (SPARCC) scores averaged 8.08 for patients with r-axSpA compared with 4.37 for patients with nr-axSpA, the study found.

Erosion damage affected 65.84% of patients with r-axSpA and 88.23% of those with nr-axSpA. Otherwise, the frequency of structural lesions was higher in patients with r-axSpA compared with nr-axSpA: backfill (33.17% vs 13.73%), fat metaplasia (79.21% vs 60.78%), and ankylosis (37.13% vs 1.96%), researchers reported. Patients with r-axSpA compared with nr-axSpA also had higher average scores for fat metaplasia (8.93 vs 4.06) and ankylosis (4.49 vs 0.04).

“Prospective study is necessary to understand the relationship between structural damages and treatments,” researchers advised.

Reference:
Tu L, Lin C, Xie Y, et al. Active Inflammatory and Chronic Structural Damages of Sacroiliac Joint in Patients With Radiographic Axial Spondyloarthritis and Non-Radiographic Axial Spondyloarthritis. Front Immunol. 2021;12:700260. Published 2021 Jul 27. doi:10.3389/fimmu.2021.700260