Patients With nr-axSpA and r-axSpA Show Differences in Several Key Criteria

A team of investigators at the at Hospital General de Mexico and the Instituto Nacional de la Nutrición identified a number of differences between patients diagnosed with nonradiographic axial spondyloarthritis (nr-axSpA) and radiographic axial spondyloarthritis (r-axSpA), according to their article in Science Reports.

Overall, patients with r-axSpA were predominantly male, with a younger presentation age and a higher prevalence of HLA-B27, the researchers found. This group also was more likely to have a history of uveitis, fewer episodes of dactylitis, more axial enthesopathy, and higher disease activity than patients with nr-axSpA.

The study included all patients who attended outpatient spondylarthritis (SpA) clinics from 1998 to 2005 and who met the diagnostic criteria for SpA. These patients were then classified by European Spondyloarthropathy Study Group criteria (ESSG). Patients with axial presentation were classied as r-axSpA if they met modified New York (mNY) criteria for sacroiliitis and as nr-axSpA if they did not. Of 148 SpA patients, 55 (37.2%) patients were diagnosed with r-axSpA, and 70 (47.3%) with nr-axSpA.

“The nr-axSpA patients had a lower proportion of males (58.6% vs 78.2%, P < 0.05), lower HLA-B27 frequency (54.3%. vs. 92.7%, P < 0.05), were older at disease onset (21 vs 16 years; P < 0.01) and had a higher frequency of infections at disease onset (9.1% vs 32.9, P < 0.05) than r-axSpA,” the authors reported. Patients with nr-axSpA had lower scores on the Bath Ankylosing Spondylitis Functional Index (BASFI) (2.9 vs 4.8; P < 0.0001), Dougados functional index (7 vs. 14; P < 0.05), and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) (4.1 vs. 5.2; P < 0.001) than those with r-axSpA, respectively.

“The factors that most influenced the presentation of r-axSpA were history of uveitis (OR 14, 95% CI 2.3–85), HLA-B27 (OR 7.97, 95% CI, 2.96–122), male sex (OR 6.16, 95% CI, 1.47–25.7), and axial enthesopathy count (OR 1.17 95% CI, 1.03–1.33),” the researchers reported.  

Reference:

Londono J, Pacheco-Tena C, Santos AM, et al. Differences between radiographic and non-radiographic axial spondyloarthritis patients in a Mexican cohort. Sci Rep; 2024;14:10342 https://doi.org/10.1038/s41598-024-61001-w