Comparison of patients with ankylosing spondylitis (AS) and non‐radiographic axial spondyloarthritis (nr‐axSpA) from a single rheumatology clinic in New Delhi

Abstract

Aim: Comparison of ankylosing spondylitis (AS) with non-radiographic axial spondyloarthritis (nr-axSpA) classified with the recent ASsessment of spondyloArthritis International Society (ASAS) criteria. Patients & Methods:This study included 288 patients clinically diagnosed as having spondyloarthritis (SpA) where a satisfactory radiograph of sacroiliac (S-I) joints was available. The AS and the nr-axSpA groups were compared for the various SpA-related variables.Results: Of 288 axSpA patients, there were 187 with AS. Of the remaining 101 patients without radiographic sacroiliitis, S-I joint magnetic resonance imaging (MRI) was available in 72; 54 of them showed active sacroiliitis thus classified as nr-axSpA according to the ASAS criteria. The remaining 18 patients with normal MRI and the other 29 patients without MRI of the S-I joints (total 47 patients), were classified as nr-axSpA using the 'clinical arm' of the ASAS criteria. On comparing the 187 AS with 101 patients in the nr-axSpA group, the AS group showed significantly more males, longer disease duration, more axial symptoms at disease onset, higher Bath Ankylosing Spondylitis Metrology Index and more syndesmophytes. Biologicals were offered significantly more often to the AS group but methotrexate as monotherapy or in combination with other disease-modifying antirheumatic drugs was offered more often in nr-axSpA group. There was no statistically significant difference between AS and nr-axSpA in other SpA parameters. Conclusion:The differences brought out between AS and nr-axSpA groups show that they may not be the same disease. A prospective long-term follow-up of large cohorts may help in clarifying if nr-axSpA is simply an early stage in the spectrum of SpA evolving into AS over time or is there inherent difference between them.

Characterization of Patients With Ankylosing Spondylitis and Nonradiographic Axial Spondyloarthritis in the US‐Based Corrona Registry

“…Our findings were consistent with those of previously published clinical trials and observational studies from outside of the US, which showed that despite some differences in patient and clinical characteristics, patients with nonradiographic axial SpA and those with AS were mostly similar and shared significant disease burden . In the current study, patients with nonradiographic axial SpA were younger, more often had enthesitis, and had better spinal mobility; however, the percentages of patients with presenteeism and overall activity impairment were significantly greater among those with nonradiographic axial SpA compared with those with AS.…”

“…This study of patients from the Corrona PsA/SpA Registry represents one of the first national‐level analyses of patients with nonradiographic axial SpA and patients with AS from multiple geographic regions and a mix of primary and tertiary clinical centers across the US. Although the criteria for classification of nonradiographic axial SpA were established in 2009 , patients with nonradiographic axial SpA have been described in only a limited number of clinical trials, registry reports, and observational studies, most of which were conducted outside of the US . In clinical trial settings, patients with nonradiographic axial SpA were typically defined as those who met the ASAS classification criteria for axial SpA but did not meet the radiology criterion of the 1984 modified New York criteria for AS, similar to the definition used in the current analysis .…”

“…Patients with nonradiographic axial SpA exhibit a substantial disease burden , although the clinical profile of these patients is still under investigation. Aside from the presence of radiographic sacroiliitis, AS has been shown to be associated with a higher prevalence of men, elevated levels of markers of inflammation, and decreased measures of spinal mobility compared with nonradiographic axial SpA . Despite these differences, previous studies have also shown that patients with AS and patients with nonradiographic axial SpA were similar regarding HLA–B27 positivity, signs of peripheral inflammation, disease activity indices, and patient‐reported outcomes .…”

“…Although data from clinical trials are useful to understand the efficacy of medications in a well‐characterized, homogeneous disease population, real‐world data from registries are helpful to understand the disease characteristics of patients realistically seen in clinical practice. A few cohort and observational studies have described the differences and similarities between patients with AS and patients with nonradiographic axial SpA; however, most of those studies were conducted outside of the US . The objective of this descriptive cross‐sectional study was to provide a nationwide clinical cohort perspective from the US through examination of the demographic, clinical, and treatment characteristics of patients with AS and patients with nonradiographic axial SpA at the time of enrollment into a US‐based registry.…”

Progression of Nonradiographic Axial Spondyloarthritis to Ankylosing Spondylitis: A Population‐Based Cohort Study

“…In several cross-sectional studies comparing patients with nonradiographic axial SpA to patients with AS, a notable finding has been a higher proportion of men with AS as compared to nonradiographic axial SpA (3,8,9,14). Men were also found to have a higher likelihood of sacroiliitis on MRI (20).…”