Current differentiation between radiographic and non-radiographic axial spondyloarthritis is of limited benefit for prediction of important clinical outcomes: data from a large, prospective, observational cohort

Abstract

ObjectiveTo compare disease characteristics and outcomes between patients with axial spondyloarthritis with non-radiographic disease (nr-axSpA), bilateral grade 2 sacroiliitis (r22axSpA) and unilateral/bilateral grade 3–4 sacroiliitis (r3+axSpA) according to the modified New York criteria.MethodsWe included patients with axial spondyloarthritis with available pelvic radiographs from the Swiss Clinical Quality Management Cohort. Retention of a first tumour necrosis factor inhibitor (TNFi) was investigated with multiple adjusted Cox proportional hazards models. The proportion of patients reaching 50% reduction in the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI50) at 1 year was assessed with multiple adjusted logistic regression analyses. Spinal radiographic progression, defined as an increase in ≥2 mSASSS units in 2 years, was assessed in generalised estimating equation models.ResultsFrom 2080 patients, those with nr-axSpA (n=485) and r22axSpA (n=443) presented with lower C reactive protein levels and less severe clinical spinal involvement compared with patients with r3+axSpA (n=1152). While TNFi retention was similar in r22axSpA and nr-axSpA, the risk of discontinuation was significantly lower in r3+axSpA (HR 0.60, 95% CI 0.44 to 0.82 vs nr-axSpA). BASDAI50 responses at 1 year were comparable in r22axSpA and nr-axSpA, with a better response associated with r3+axSpA (OR 2.05, 95% CI 1.09 to 3.91 vs nr-axSpA). Spinal radiographic progression was similar in r22axSpA and nr-axSpA and significantly higher in r3 +axSpA.ConclusionPatients with r22axSpA are comparable to nr-axSpA patients but differ from patients with more severe sacroiliac damage with regard to treatment effectiveness and spinal radiographic progression. Therefore, current differentiation between nr-axSpA and radiographic disease seems of limited use for outcome prediction.

Non‐radiographic axial spondyloarthritis in South America. Burden of disease and differential features with respect to ankylosing spondylitis at time of diagnosis. A comprehensive analysis with a focus on images

“…However, the rest of the clinical characteristics and of the disease are similar between one group and another. [5][6][7] Although male sex, smoking and elevated C-reactive protein have been classically described as radiographic progression risk factors, 20,21 in this study only male sex was more frequent in AS patients compared with nr-axSpA patients, with no difference regarding inflammatory markers. In smoking status, a difference was observed with 51% vs 34% in patients with AS and nr-axSpA, but this was not statistically significant.…”

“…In the present work it can be observed how patients with AS have a significantly higher percentage of men, and a longer diagnostic delay. However, the rest of the clinical characteristics and burden of the disease are similar between one group and another 5–7 …”

“…It has been proven that disease activity and functional impact are similar in nr-axSpA and AS, maintaining an equal burden of the disease regardless of the radiographic progression. 6,7 Previous investigations have shown that the characteristics of patients with axSpA in Latin America differ from those of patients from North America or Europe from the genetic and phenotypic point of view, with a lower prevalence of HLA-B27 and greater peripheral involvement. [8][9][10] There are descriptions of axSpA cohorts in American countries, but no comparisons that would give us information regarding the similarities and differences between nr-axSpA and radiographic axSpA (r-axSpA), especially in terms of sacroiliac joint MRI image characteristics.…”

“…In contrast, many cohorts, especially from European countries, have shown that patients with non‐radiographic forms can progress to radiographic stages, with male gender, presence of HLA‐B27, and high levels of C‐reactive protein as risk factors for progression. It has been proven that disease activity and functional impact are similar in nr‐axSpA and AS, maintaining an equal burden of the disease regardless of the radiographic progression 6,7 …”

“…1 [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. and sclerosis (OR 7.6, 95% CI 1.4-41).…”