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

Abstract

Background: Non-radiographic axial spondyloarthritis (nr-axSpA) data from South America are scarce, especially regarding image features. ObjectiveTo estimate the frequency of nr-axSpA and ankylosing spondylitis (AS) in a cohort of Argentinian patients with chronic low back pain (LBP) and to analyze the difference between both, with focus on magnetic resonance imaging (MRI) lesions, at diagnosis. Methods:Patients with LBP and a diagnosis of axSpA who participated in a reumacheck program were included. All patients with a suspicion of SpA were evaluated using blood analytics, HLA-B27, and images (MRI). Sociodemographic data, SpA features, diagnostic dela,y and clinimetrics were assessed by an operator who was blinded to the patient's test results. On MRI, the presence of SpA lesions was assessed and a concordance exercise was carried out between rheumatologists and radiologist.Result: Of 198 LBP patients, 97 had axSpA, 54% of whom were nr-axSpA. A positive MRI was found in 50%. No difference in terms of disease activity, functional impact, laboratory or treatments between nr-axSpA and AS were found. Higher frequencies of male sex and chronic lesions on sacroiliac MRI were found in AS patients. In the logistic regression, an independent association with AS diagnosis was found: male (odds ratio [OR] 4.8), MRI fat replacement (OR 4.6), MRI sclerosis (OR 7.6), and diagnostic delay of more than 2 years (OR 10). The concordance between rheumatologists and radiologists was considered good to very good (κ 0.7-0.8). Conclusion:The frequency of nr-axSpA was 54%. We found a higher frequency of being male, more SpA features, and a longer diagnostic delay in patients with AS.Patients with AS had more structural lesions, with a good concordance between rheumatologist and radiologist.

Clinical, Laboratory, and Imaging Features Between Men and Women With Axial Spondyloarthritis in a Specialized Center in Argentina

“…It is widely known that men have greater radiographic involvement, especially when comparing nonradiographic and radiographic axial SpA cohorts, in the latter where the frequency in women is higher. 19,20 However, there are few reports on the evaluation of MRI; in our investigation, we obtained MR images in all the patients with the evaluation of acute and chronic lesions, but we only observed significant differences in the presence of bone bridges in men. It has been established that there are anatomical reasons that could influence the lower degree of inflammation and progression in women due to a smaller joint surface with enthesis.…”

“…The most relevant finding was the greater radiographic compromise in the sacroiliac joints, which was an independent variable in the logistic regression analysis. It is widely known that men have greater radiographic involvement, especially when comparing nonradiographic and radiographic axial SpA cohorts, in the latter where the frequency in women is higher 19,20 . However, there are few reports on the evaluation of MRI; in our investigation, we obtained MR images in all the patients with the evaluation of acute and chronic lesions, but we only observed significant differences in the presence of bone bridges in men.…”

Differences between radiographic and non-radiographic axial spondyloarthritis patients in a Mexican cohort

“…Patients with r-axSpA had an earlier disease onset, around 16 years old, and experienced a more prolonged cumulative inflammatory spinal pain during follow-up than nr-axSpA. Published evidence about the relationship between age and SpA subgroup has been contradictory; studies such as the one by Poddubnyy D et al, 14 that included Latin-American patients, Rudwaleit et al 15 , and Kiltz et al, 16 in a German population, Kishimoto et al, 17 using data from ASAS-COMOSPA study, and Garcia Salinas et al 18 in Argentinian cohort of patients with chronic low back pain did not find differences between age and SpA subgroup. A multinational study with 914 African, Asian, and European patients, which included only 26 (2.8% of the total) Latin American patients, also found no differences 19 .…”

Spondyloarthritis and the microbiota: Where are we now?

“…Axial types include the classic ankylosing spondylitis, non-radiographic axial SpA, axial psoriatic arthritis, axial reactive arthritis, and inflammatory bowel diseases associated with SpA. Peripheral types refer to peripheral psoriatic arthritis and peripheral reactive arthritis [1][2][3][4] What types of bacteria are potentially the pivot of SpA pathogenesis?…”

“…Generally speaking, SpA is now defined as two major subtypes, axial SpA (axSpA) and peripheral SpA (pSpA). Within the category of axSpA, diseases can be divided into two groups based on their radiographic findings, with and without radiographic sacroiliitis, as radiographic axSpA (r‐axSpA; also known as ankylosing spondylitis) and non‐radiographic axSpA (nr‐axSpA) 1 respectively. Some studies also considered several subtypes as axSpA, including axial psoriatic arthritis (axPsA), axial reactive arthritis (ReA), and inflammatory bowel diseases associated with SpA (SpA‐IBD).…”