Comparison of the effect of treatment with NSAIDs added to anti-TNF therapy versus anti-TNF therapy alone on the progression of structural damage in the spine over 2 years in patients with radiographic axial spondyloarthritis from the randomised-controlled CONSUL trial.

OBJECTIVES: The study aimed to evaluate the effect of adding a non-steroidal anti-inflammatory drug (NSAID), celecoxib (CEL), to a tumour necrosis factor inhibitor (TNFi), golimumab (GOL), compared with TNFi monotherapy on radiographic spinal progression in patients with radiographic axial spondyloarthritis (r-axSpA) over 2 years. METHODS: R-axSpA patients, having risk factors for radiographic progression (high disease activity plus C reactive protein >5 mg/L and/or ≥1 syndesmophyte(s)), underwent a 12-week run-in phase with GOL 50 mg every 4 weeks. In the core phase (96 weeks), only patients with a good clinical response at week 12 were randomised (1:1) to GOL+CEL 200 mg two times per day (combination therapy) or GOL monotherapy. The primary endpoint was radiographic progression assessed by modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) change at week 108 in the intent-to-treat population. RESULTS: A total of 128 patients were enrolled in the run-in phase; and 109 patients were randomised at week 12 to monotherapy (n=55) or combination therapy (n=54). At week 108, 97 (52 vs 45) patients completed the study. The change in mSASSS at week 108 was 1.7 (95% CI 0.8 to 2.6) in the monotherapy vs 1.1 (95% CI 0.4 to 1.8) in the combination therapy groups (p=0.79). New syndesmophytes occurred in 25% of patients in the monotherapy vs 11% of patients in the combination therapy groups (p=0.12). During the study, no significant differences in adverse events and serious adverse events were observed between the groups. CONCLUSIONS: Combination therapy with GOL+CEL did not demonstrate statistically significant superiority over GOL monotherapy in retarding radiographic spinal progression over 2 years in r-axSpA.

Impact of body composition on clinical outcomes in patients with active radiographic axial spondyloarthritis under biological therapy.

OBJECTIVE: To assess the association of body composition, evaluated by bioimpedance analysis (BIA), with disease activity, physical function, and mobility in patients with axSpA undergoing bDMARD treatment for one year. METHODS: Patients with AS (radiographic axSpA) were enrolled in an extension of the German Spondyloarthritis Inception Cohort (GESPIC). Patients were required to be candidates for bDMARD therapy at baseline presenting high disease activity despite previous treatment with nonsteroidal anti-inflammatory drugs. Outcomes (disease activity, function, and mobility) and body composition parameters were assessed at baseline and every 6 months thereafter. Body composition was assessed by BIA. The association between body composition parameters and outcomes over 1 year was analyzed using longitudinal generalized estimating equations. RESULTS: Seventy-four patients with radiographic axSpA were included in current analysis with a mean age of 36.5 years, disease duration of 6.2 years and ASDAS-CRP score of 3.4 at baseline. Fat mass value and fat mass index were positively associated with disease activity (ASDAS: ß = 0.01, 95% CI [-0.01, 0.03] and ß = 0.04, 95% CI [-0.01, 0.08], respectively) and functional disability (BASFI). Visceral adipose tissue (VAT) was associated with reduced spine mobility (BASMI: ß = 0.20, 95% CI [0.07, 0.33]). Additionally, increase in VAT and fat mass parameters was linked to worse disease activity and functional disability in women, while they were strongly associated with reduced spinal mobility in men. CONCLUSIONS: Higher levels of body fat and VAT were positively associated with increased disease activity, functional disability, and reduced spinal mobility in patients with radiographic axSpA treated with bDMARDs.

Anatomical variation of the sacroiliac joint carries an increased risk for erosion and bone marrow oedema in axial spondyloarthritis.

OBJECTIVES: To assess the impact of joint shape variations on inflammatory lesions on SI joint MRIs in patients with axial spondyloarthritis (axSpA). METHODS: A total of 1194 patients from four different prospective cohorts were evaluated, with 684 (57.3%) having sufficient imaging data for inclusion (379 axSpA, 305 controls). All images were evaluated for joint form, erosion, sclerosis, fat metaplasia and bone marrow oedema (BMO) by two independent readers. Logistic regression analyses were used to assess the association of joint form and lesions on imaging for axSpA patients and controls. RESULTS: Atypical joint forms were common in both axSpA (43.5% [154/354]) and control patients (44.2% [134/303]); both intra-articular variants and a crescent joint shape were significantly more common in axSpA patients (18.4% vs 11.6% and 11.0% vs 5.3.%, respectively; P < 0.001). The axSpA patients with intra-articular joint form variants had 2-fold higher odds of exhibiting erosions [odds ratio (OR) 2.09 (95% CI 1.18, 3.69)] and BMO [OR 1.79 (95% CI 1.13, 2.82)]; this association was not observed in controls. Accessory joints increased the odds for sclerosis in axSpA patients [OR 2.54 (95% CI 1.10, 5.84)] and for sclerosis [OR 17.91 (95% CI 6.92, 46.37)] and BMO [OR 2.05 (95% CI 1.03, 4.07)] in controls. CONCLUSIONS: Joint form variations are associated with the presence of inflammatory lesions on SI joint MRIs of axSpA patients. This should be taken into consideration in future research on the interplay of mechanical strain and inflammation in axSpA.

Self-reported diagnostic confidence predicts diagnostic accuracy in axial spondyloarthritis imaging.

OBJECTIVES: Reporting diagnostic confidence (DC) in axial spondyloarthritis (axSpA) imaging is recommended by the ASAS guidelines. Our aim was to investigate whether self-reported DC predicts diagnostic accuracy in axSpA imaging using X-ray (XR), computed tomography (CT) and magnetic resonance imaging (MRI). METHODS: We performed a post hoc analysis including 163 patients with low back pain (89 axSpA and 56 non-axSpA). Nine blinded readers with different experience levels (inexperienced (< 1 year), semi-experienced (3-8 years) and experienced (> 12 years)) scored the sacroiliac joint images for compatibility with axSpA. DC was reported on a scale from 1 (not sure) to 10 (very sure). Mean DC scores and standard deviations were calculated for correct and incorrect responses using XR, CT, MRI, XR+MRI and CT+MRI. Differences in DC were assessed using the Mann-Whitney U test. RESULTS: DC scores were higher for correct axSpA diagnoses and differed significantly between correct and incorrect responses for all modalities (p< 0.001), with a mean DC of 7.1 ± 2.1 and 6.3 ± 2.1 for XR, 8.3 ± 1.8 and 6.7 ± 2.0 for CT, 8.1 ± 1.9 and 6.2 ± 1.9 for MRI, 8.2 ± 1.8 and 6.7 ± 1.8 for XR+MRI and 8.4 ± 1.8 and 6.8 ± 1.8 for CT+MRI, respectively. This was also the case when looking at the results by experience group, except for XR in the inexperienced group. CONCLUSION: Providing self-reported DC in radiological reports is useful information to predict diagnostic reliability in axSpA imaging.

Deep Learning Detects Changes Indicative of Axial Spondyloarthritis at MRI of Sacroiliac Joints.

Background MRI is frequently used for early diagnosis of axial spondyloarthritis (axSpA). However, evaluation is time-consuming and requires profound expertise because noninflammatory degenerative changes can mimic axSpA, and early signs may therefore be missed. Deep neural networks could function as assistance for axSpA detection. Purpose To create a deep neural network to detect MRI changes in sacroiliac joints indicative of axSpA. Materials and Methods This retrospective multicenter study included MRI examinations of five cohorts of patients with clinical suspicion of axSpA collected at university and community hospitals between January 2006 and September 2020. Data from four cohorts were used as the training set, and data from one cohort as the external test set. Each MRI examination in the training and test sets was scored by six and seven raters, respectively, for inflammatory changes (bone marrow edema, enthesitis) and structural changes (erosions, sclerosis). A deep learning tool to detect changes indicative of axSpA was developed. First, a neural network to homogenize the images, then a classification network were trained. Performance was evaluated with use of area under the receiver operating characteristic curve (AUC), sensitivity, and specificity. P < .05 was considered indicative of statistically significant difference. Results Overall, 593 patients (mean age, 37 years ± 11 [SD]; 302 women) were studied. Inflammatory and structural changes were found in 197 of 477 patients (41%) and 244 of 477 (51%), respectively, in the training set and 25 of 116 patients (22%) and 26 of 116 (22%) in the test set. The AUCs were 0.94 (95% CI: 0.84, 0.97) for all inflammatory changes, 0.88 (95% CI: 0.80, 0.95) for inflammatory changes fulfilling the Assessment of SpondyloArthritis international Society definition, and 0.89 (95% CI: 0.81, 0.96) for structural changes indicative of axSpA. Sensitivity and specificity on the external test set were 22 of 25 patients (88%) and 65 of 91 patients (71%), respectively, for inflammatory changes and 22 of 26 patients (85%) and 70 of 90 patients (78%) for structural changes. Conclusion Deep neural networks can detect inflammatory or structural changes to the sacroiliac joint indicative of axial spondyloarthritis at MRI. © RSNA, 2022 Online supplemental material is available for this article.

Treatment with tumour necrosis factor inhibitors is associated with a time-shifted retardation of radiographic spinal progression in patients with axial spondyloarthritis.

OBJECTIVE: The objective of the current study was to analyse the association between treatment with tumour necrosis factor inhibitors (TNFi) and radiographic spinal progression in patients with axial spondyloarthritis (axSpA) from a long-term inception cohort. METHODS: A total of 243 patients with axSpA from the German Spondyloarthritis Inception Cohort with at least two sets of spinal radiographs obtained at least 2 years apart during a 10-year follow-up were included. Spinal radiographs were evaluated by three trained and calibrated readers according to the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). The association between the current TNFi, previous TNFi and radiographic spinal progression defined as the absolute mSASSS change score over 2 years was analysed using longitudinal generalised estimating equations analysis. RESULTS: TNFi treatment in the current 2-year interval was not associated with retardation of radiographic spinal progression (ß=-0.02 (95% CI -0.37 to 0.34) and -0.17 (95% CI -0.54 to 0.20) for any and ≥12 months treatment duration, respectively, adjusted for sex, the Ankylosing Spondylitis Disease Activity Score, smoking, presence of definite radiographic sacroiliitis, mSASSS at baseline and non-steroidal anti-inflammatory drug intake). TNFi treatment in the previous 2-year interval, was, however, significantly associated with reduction of mSASSS progression, which was especially evident in patients who received TNFi in the previous and in the current intervals: ß=-0.58 (95% CI -1.02 to -0.13), adjusted for the same variables. CONCLUSION: TNFi treatment was associated with a time-shifted effect on radiographic spinal progression in axSpA that became evident between years 2 and 4 after treatment initiation.

Early identification of axial psoriatic arthritis among patients with psoriasis: a prospective multicentre study.

OBJECTIVES: To evaluate a dermatologist-centred screening tool followed by a structured rheumatological examination including MRI of sacroiliac joints and spine for the recognition of psoriatic arthritis with axial involvement (axPsA). METHODS: This was a prospective multicentre study. Adult patients with a confirmed diagnosis of psoriasis who had chronic back pain (≥3 months), onset <45 years and had not been treated with any biologic or targeted synthetic disease-modifying antirheumatic drug in the 12 weeks before screening were referred to a specialised rheumatology clinic. A rheumatological investigation including clinical, laboratory and genetic assessments as well as imaging with conventional radiography and MRI of sacroiliac joints and spine was performed. The primary outcome of the study was the proportion of patients diagnosed with axPsA among all referred patients with PsO. RESULTS: Rheumatologists examined 100 patients of those who qualified for referral. 14 patients (including 3 with both axial and peripheral involvement) were diagnosed with axPsA and 5 were diagnosed with peripheral PsA solely. All patients diagnosed with axPsA had active inflammatory and/or structural (post)inflammatory changes in the sacroiliac joints and/or spine on imaging. In five patients, MRI changes indicative of axial involvement were found only in the spine. All but one patient with PsA (13/14 with axPsA and 5/5 with pPsA) fulfilled the Classification Criteria for Psoriatic Arthritis criteria for PsA. The Assessment of SpondyloArthritis International Society criteria for axSpA were fulfilled in 9 (64.3%) patients diagnosed with axPsA. CONCLUSIONS: Applying a dermatologist-centred screening tool may be useful for the early detection of axPsA in at-risk patients with psoriasis .

The impact of psoriasis on the clinical characteristics, disease burden and treatment patterns of peripheral spondyloarthritis.

OBJECTIVES: To evaluate the clinical characteristics, disease burden, and treatment patterns of peripheral spondyloarthritis (pSpA) patients with and without psoriasis using data from the ASAS-perSpA study. METHODS: We included 433 patients who had a diagnosis of pSpA according to the rheumatologist's diagnosis from the ASAS-PerSpA study. The presence of a personal history of psoriasis was defined as the presence of signs of psoriasis at physical examination or the presence of psoriatic nail dystrophy, including onycholysis, pitting and hyperkeratosis, or a history of psoriasis diagnosed by a physician. Clinical characteristics, patient-reported outcomes and treatment pattern were compared between subgroups with and without psoriasis. RESULTS: A total of 83 patients (19.2%) had a personal history of psoriasis. Patients with psoriasis were older (48.4 vs 43.2 years) and had a longer diagnostic delay (7.4 vs 3.5 years), a higher frequency of dactylitis (36.1 vs 20.0%) and enthesitis (65.1 vs 55.4%) than patients without psoriasis. A longer diagnostic delay (odds ratio [OR] = 1.06 [95% CI 1.01, 1.11]), lower odds for HLA-B27 positivity (OR = 0.31 [95% CI 0.15, 0.65]) and higher odds for enthesitis (OR = 2.39 [95% CI 1.16, 4.93]) were associated with the presence of psoriasis in a multivariable regression analysis. While patient-reported outcomes were comparable between groups, a higher use of biologic DMARDs was observed in patients with vs without psoriasis. CONCLUSION: The presence of psoriasis has an impact on clinical characteristics of pSpA. pSpA patients without psoriasis were less frequently treated with biologic DMARDs despite similar disease burden as compared with patients with psoriasis.

Elucidating the role of a positive family history in differentiating between axial and peripheral spondyloarthritis: an ancillary analysis of the ASAS-PerSpA study.

OBJECTIVES: Positive family history (PFH) of spondyloarthritis (SpA) is important in the diagnosis of SpA. However, the contribution of a PFH in differentiating the two SpA subtypes (axial and peripheral spondyloarthritis (pSpA)), in particular the importance of second-degree relative (SDR) has not been well-studied. We aimed to investigate whether PFH of radiographic axial spondyloarthritis (r-axSpA), psoriasis, uveitis, reactive arthritis and inflammatory bowel disease in first-degree relative (FDR) and second-degree relative (SDR) contributes to differentiation between axSpA and pSpA using the data from a multinational cohort study. METHODS: The ASAS-PerSpA study dataset was used to assess the effects of a PFH on differentiating between axSpA and pSpA via generalised structural equation modelling. Model building using backward selection was performed to obtain a final model. Direct, indirect and total effects of the path analysis were calculated. RESULTS: A total of 3803 patients were included: 2458 axSpA and 1345 pSpA patients. FDR (OR: 3.75, 95% CI: 2.86-4.91, p<0.001) and SDR (OR: 4.58, 95% CI: 3.19-6.59, p<0.001) with r-axSpA were positively associated while FDR (OR: 0.262, 95% CI: 0.207-0.331, p<0.001) and SDR (OR: 0.305, 95% CI: 0.221-0.420, p<0.001) with psoriasis were negatively associated with differentiating patients with axSpA from pSpA. CONCLUSIONS: The presence of r-axSpA and psoriasis in FDR or SDR are useful in differentiating axSpA from pSpA. SDR with r-axSpA may contribute greater towards the differentiation than FDR. Clinicians should consider taking an extensive family history of SpA and their subtypes to better differentiate the subtypes within the SpA spectrum.

Diagnosing axial spondyloarthritis: estimation of the disease probability in patients with a priori different likelihoods of the diagnosis.

OBJECTIVE: To evaluate the diagnostic value of SpA parameters and their combination for the diagnosis of axial SpA in patients with an a priori different probability of the diagnosis. METHODS: A total of 361 patients with chronic back pain and suspicion of axial SpA (181 referred by primary care physicians or orthopaedists, 180 recruited via an online screening tool) received a structured rheumatologic examination, which resulted into a diagnosis or exclusion of axial SpA. The prevalence of axial SpA indicating the pre-test probability was 40% in the physician-referred subgroup and 20% in the online screening subgroup. Sensitivities, specificities and likelihood ratios for SpA features were determined in both subgroups and the respective post-test probabilities of axial SpA were calculated. RESULTS: The relative diagnostic value of single SpA features varied substantially between the groups with different referral pathways. For instance, HLA-B27 positivity increased the probability of the presence of axial SpA by 35% to 55% in online-screened patients and by 22% to 62% in physician-referred patients. The absence of HLA-B27 resulted in a sharp decrease in the probability of the presence of axial SpA in physician-referred patients (from 40% to 6%). This decrease was less sharp in the online screening group (from 20% to 10%). These differences were especially relevant in patients with a small number (one to two) of positive SpA features. CONCLUSION: The diagnostic value of SpA features varies in different patient populations, which should be considered in the diagnostic approach.

Relation of α2-Antiplasmin Genotype and Genetic Determinants of Fibrinogen Synthesis and Fibrin Clot Formation with Vascular Endothelial Growth Factor Level in Axial Spondyloarthritis.

OBJECTIVE: Coagulation and fibrinolysis are interrelated with the expression of vascular endothelial growth factor (VEGF), which frequently is increased in axial spondyloarthritis (axSpA). We tested whether (i) α2-antiplasmin (A2AP) Arg6Trp, (ii) fibrinogen, factor XIII A-subunit or B-subunit genotypes are associated with VEGF levels and assessed whether the known association between elevated VEGF and radiographic spinal progression in axSpA depends on genetic background. METHODS: One hundred and eighty-six axSpA patients from the German Spondyloarthritis Inception Cohort were genotyped, characterized for VEGF levels, and statistically analyzed. The association between VEGF and radiographic spinal progression was assessed in dependence on genetic background in stratified analyses. RESULTS: A2AP 6Trp carriage was associated with VEGF elevation (OR: 2.37, 95% CI: 1.06-5.29) and VEGF levels (6Trp, 455 ± 334 pg/mL; 6Arg/Arg, 373 ± 293 pg/mL; p < 0.008). Association between elevated VEGF and radiographic spinal progression in axSpA (OR: 3.11, 95% CI: 1.02-8.82) depended remarkably on the fibrinogen (FGA) genotype. When considering axSpA patients with elevated VEGF, in FGA rs6050A>G wild types, 42.1% of patients (8 of 19) progressed, while in G-allele carriers, no radiographic progression happened (0 of 13) (p < 0.04). CONCLUSIONS: The A2AP Arg6Trp genotype seems to influence VEGF levels in axSpA. The predictive value of VEGF elevations in respect of radiographic spinal progression in axSpA depends on FGA genotypes.

Association of nociplastic and neuropathic pain components with the presence of residual symptoms in patients with axial spondyloarthritis receiving biological disease-modifying antirheumatic drugs.

OBJECTIVE: To evaluate the association of nociplastic (NoP) and neuropathic pain (NP) components with residual symptoms in patients with radiographic axial spondyloarthritis (r-axSpA) receiving biological disease-modifying antirheumatic drugs (bDMARDs). METHODS: 78 patients with r-axSpA from the GErman SPondyloarthritis Inception Cohort receiving a bDMARD for at least 3 months were included in this analysis. The Widespread Pain Index (WPI) and the PainDETECT (PD) questionnaire were used to quantify the NoP and the NP components, respectively. Axial Spondyloarthritis Disease Activity Score (ASDAS) and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) were used as measures of residual symptoms. C reactive protein (CRP) was used as a measure of systemic inflammatory activity. Univariable and multivariable regression analyses of disease activity were performed. The regions of the WPI score and items of the PD score were used for cluster analyses. RESULTS: Linear multivariable regression analysis showed that WPI and PD were independently associated with ASDAS (b=0.1, 95% CI 0.04 to 0.17, and b=0.05, 95% CI 0.02 to 0.08, respectively) and BASDAI (b=0.24, 95% CI 0.08 to 0.39, and b=0.17, 95% CI 0.1 to 0.25, respectively) in r-axSpA patients receiving stable treatment with bDMARDs. Furthermore, WPI and PD were found to be significantly associated with the presence of relevant residual symptoms as defined by BASDAI ≥4 (OR 1.93, 95% CI 1.09 to 4.15, and OR 1.32, 95% CI 1.04 to 1.85, respectively). The effects were present also in patients with normal level of CRP. Cluster analysis revealed three distinct pain distribution profiles and four specific sensory symptom constellations allowing differentiation of different pain subtypes. CONCLUSION: Both NoP and NP components seem to be associated with residual symptoms in patients with r-axSpA receiving treatment with bDMARDs.

Diagnostic accuracy in axial spondyloarthritis: a systematic evaluation of the role of clinical information in the interpretation of sacroiliac joint imaging.

OBJECTIVES: Radiography and MRI of the sacroiliac joints (SIJ) are relevant for the diagnosis and classification of patients with axial spondyloarthritis (axSpA). This study aimed to evaluate the impact of clinical information (CI) on the accuracy of imaging interpretation. METHODS: Out of 109 patients referred because of suspicion of axSpA with complete imaging sets (radiographs and MRI of SIJ), 61 were diagnosed with axSpA (56%). Images were independently evaluated by three radiologists in four consecutive reading campaigns: radiographs and radiographs+MRI without and with CI including demographic data, SpA features, physical activity and pregnancy. Radiographs were scored according to the modified New York criteria, and MRIs for inflammatory and structural changes compatible with axSpA (yes/no). The clinical diagnosis was taken as reference standard. The compatibility of imaging findings with a diagnosis of axSpA (precision) before and after the provision of CI and radiologists' confidence with their findings (0-10) were evaluated. RESULTS: The precision of radiographs evaluation without versus with CI increased from 70% to 78% (p=0.008), and for radiographs+MRI from 81% to 82% (p=1.0), respectively. For CR alone, the sensitivity and specificity of radiologic findings were 51% and 94% without and 60% and 100% with CI, while, for radiographs+MRI, they were 74% and 90% vs 71% and 98%, respectively. The diagnostic confidence of radiologists increased from 5.2±1.9 to 6.0±1.7 with CI for radiographs, and from 6.7±1.6 to 7.2±1.6 for radiographs+MRI, respectively. CONCLUSION: The precision, specificity and diagnostic confidence of radiologic evaluation increased when CI was provided.

Shared and Distinct Gut Microbiota in Spondyloarthritis, Acute Anterior Uveitis, and Crohn's Disease.

OBJECTIVE: Spondyloarthritis (SpA) is a group of immune-mediated diseases highly concomitant with nonmusculoskeletal inflammatory disorders, such as acute anterior uveitis (AAU) and Crohn's disease (CD). The gut microbiome represents a promising avenue to elucidate shared and distinct underlying pathophysiology. METHODS: We performed 16S ribosomal RNA sequencing on stool samples of 277 patients (72 CD, 103 AAU, and 102 SpA) included in the German Spondyloarthritis Inception Cohort and 62 back pain controls without any inflammatory disorder. Discriminatory statistical methods were used to disentangle microbial disease signals from one another and a wide range of potential confounders. Patients were naive to or had not received treatment with biological disease-modifying antirheumatic drugs (DMARDs) for >3 months before enrollment, providing a better approximation of a true baseline disease signal. RESULTS: We identified a shared, immune-mediated disease signal represented by low abundances of Lachnospiraceae taxa relative to controls, most notably Fusicatenibacter, which was most abundant in controls receiving nonsteroidal antiinflammatory drug monotherapy and implied to partially mediate higher serum C-reactive protein. Patients with SpA showed an enrichment of Collinsella, whereas human leukocyte antigen (HLA)-B27+ individuals displayed enriched Faecalibacterium. CD patients had higher abundances of a Ruminococcus taxon, and previous conventional/synthetic DMARD therapy was associated with increased Akkermansia. CONCLUSION: Our work supports the existence of a common gut dysbiosis in SpA and related inflammatory pathologies. We reveal shared and disease-specific microbial associations and suggest potential mediators of disease activity. Validation studies are needed to clarify the role of Fusicatenibacter in gut-joint inflammation, and metagenomic resolution is needed to understand the relationship between Faecalibacterium commensals and HLA-B27.

Exploring complement biomarkers in suspected axial spondyloarthritis.

OBJECTIVES: To investigate lectin pathway proteins (LPPs) as biomarkers for axial spondyloarthritis (axSpA) in a cross-sectional cohort with a suspicion of axSpA, comprising newly diagnosed axSpA and chronic low back pain (cLBP) individuals. METHODS: Serum samples from 515 participants within the OptiRef cohort, including 151 axSpA patients and 364 cLBP patients, were measured using immunoassays for LPPs (mannan-binding lectin (MBL), collectin liver-1 (CL-L1), M-ficolin, H-ficolin and L-ficolin, MBL-associated serine proteases (MASP)-1, -2 and -3, MBL-associated proteins (MAp19 and MAp44) and the complement activation product C3dg). RESULTS: Serum levels of L-ficolin, MASP-2 and C3dg were elevated in axSpA patients, whereas levels of MASP-3 and CL-L1 were decreased, and this remained significant for C3dg and MASP-3 after adjustment for C reactive protein (CRP). A univariate regression analysis showed serum levels of CL-L1, MASP-2, MASP-3 and C3dg to predict the diagnosis of axSpA, and MASP-3 and C3dg remained significant in a multivariate logistic regression analysis. Assessment of the diagnostic potential showed that a combination of human leukocyte antigen B27 (HLA-B27) and measurements of L-ficolin, MASP-3 and C3dg increased the diagnostic specificity for axSpA, however, with a concomitant loss of sensitivity. CONCLUSIONS: Serum levels of complement activation, that is, C3dg, and MASP-3 differed significantly between axSpA and cLBP patients after adjustment for CRP. Although combining HLA-B27 with measurements of L-ficolin, MASP-3 and C3dg increased the diagnostic specificity for axSpA, this seems unjustified due to the concomitant loss of sensitivity. However, both C3dg and MASP-3 were associated with axSpA diagnosis in multivariate logistic regression, suggesting an involvement of complement in the inflammatory processes and possibly pathogenesis in axSpA.

Comparing clinical profiles in spondyloarthritis with Crohn's disease or ulcerative colitis: insights from the ASAS-PerSpA study.

Objectives: Assuming SpA manifestations may vary among patients with different inflammatory bowel disease (IBD) subtypes, we explored the clinical characteristics associated with the presence of Crohn's disease (CD) or ulcerative colitis (UC) in patients with spondyloarthritis (SpA). Methods: We included 3152 patients of ASAS-PerSpA study diagnosed with either axial SpA or peripheral SpA, according to their treating rheumatologist. Of these, 146 (4.6%) had confirmed IBD by endoscopy and were categorized into CD or UC groups. Demographics, clinical characteristics, treatments and patient-reported outcomes were compared between the two subgroups. Results: From 146 patients included in the current analysis, 87 (59.6%) had CD [75 (86.2%) axial SpA and 12 (13.8%) peripheral SpA], and 39 (26.7%) had UC [34 (87.2%) axial SpA and 5 (12.8%) peripheral SpA]. CD and UC groups had similar age with average of 44.9 (13.5) vs 44.0 (13.0) years, respectively, and a slight male predominance in CD (63.2%) compared with UC (51.3%). Diagnostic delay for SpA was 7.0 (6.9) years for CD and 8.8 (8.1) years for UC. Chronic back pain was the most reported symptom present in 95.4% of CD patients and 89.7% of UC patients. Both groups had similar musculoskeletal phenotyping, with higher frequency of psoriasis (15.4%) and uveitis 28.2% in UC; and higher tendency to be HLA-B27 positive in CD (51.9% in CD vs.s 39.4% in UC). Conclusion: In our analysis patients with SpA and concurrent CD or UC had mainly similar musculoskeletal phenotypes. However, they differ slightly in extra-musculoskeletal manifestations and HLA-B27 prevalence.