Do quality of life and work productivity change in early axial spondyloarthritis and non-axial spondyloarthritis patients after two years?

OBJECTIVE: To compare health-related quality of life (HRQoL) and work productivity in axial spondyloarthritis (axSpA) and non-axSpA patients with chronic back pain of < 2 years (2 y). METHODS: Baseline and 2 y data of patients included in the SPondyloArthritis Caught Early cohort were analyzed. HRQoL was assessed by the physical (PCS) and mental component summary (MCS) scores of the 36-Item Short-Form Health Survey; and presenteeism, absenteeism, work productivity loss (WPL) and activity impairment (AI) by the Work Productivity and Activity Impairment questionnaire. Linear or zero-inflated negative binomial regression was conducted to compare 2 y outcomes between groups (axSpA and non-axSpA), adjusting for the baseline value, sex, age and use of nonsteroidal anti-inflammatory drugs. RESULTS: There were 265 axSpA and 108 non-axSpA patients: males 52% vs 26%, mean age 29 vs 31 years, respectively. At baseline, non-axSpA patients showed worse PCS (mean 28.6 axSpA vs 26.6 non-axSpA), presenteeism (31.1% vs 37.3%), absenteeism (8.2% vs 10.3%), WPL (34.7% vs 44.1%) and AI (39.6% vs 48.5%). MCS was not impaired in either group. After 2 y, PCS, presenteeism, WPL and AI significantly improved in both groups; absenteeism only in axSpA. In multivariable analysis, axSpA (vs non-axSpA) was associated with 22% less WPL (incidence rate ratio [95% CI]: 0.78 [0.62; 0.98]) and 18% less AI (0.82 [0.69; 0.97]). CONCLUSION: HRQoL and work productivity are more impaired in non-axSpA (vs axSpA) at baseline and still after 2 y. Although most outcomes improve in both groups, axSpA is associated with larger improvements in work productivity and activity impairment.

Inflammation in the posterior elements, in particular the facet joint and facet joint ankylosis over 2-year follow-up in radiographic axial spondyloarthritis.

OBJECTIVES: To assess the association of posterior element (PE) and facet joint (FJ) inflammation with subsequent new FJ ankylosis (FJA) on MRI, in patients with radiographic axial spondyloarthritis (r-axSpA). METHODS: Patients from the Sensitive Imaging in Ankylosing Spondylitis cohort, inclusion criteria r-axSpA and ≥1 radiographic spinal syndesmophyte, were studied. MRI of the full spinal was performed at baseline, 1 and 2 years. PE/FJ inflammatory lesions and FJA were assessed per vertebral unit (VU) level by three readers. With multilevel time-lagged autoregressive generalised estimated equations, the association between PE/FJ inflammation and the subsequent development of FJA was investigated, taking the reader and VU levels into account. RESULTS: Out of the 58 patients with at least 2 reader scores available, mean age 49 (SD 10) years, 84% men, 59% had baseline PE inflammation, 24% had FJ inflammation and 26% had FJA. PE inflammation was more prevalent in the lower thoracic spine and FJ inflammation in the upper thoracic spine. VU with PE or FJ inflammation showed subsequent new FJA in two and one VU levels, respectively. The probability of developing FJA doubled with prior FJ inflammation. In multilevel analysis, FJ inflammation was associated with subsequent FJA (OR=3.8, 95% CI: 1.5 to 9.8), while no association was found between PE inflammation and new FJA (OR=1.2 (0.6-2.4)). CONCLUSIONS: FJ inflammation is rare in severe r-axSpA, but when present, the likelihood of developing subsequent FJA is over three times higher compared with FJ without inflammation. This finding contributes to the understanding of the relationship between inflammation and ankylosis at the same anatomical location in patients with axSpA.

One-year effectiveness of long-term exercise therapy in people with axial spondyloarthritis and severe functional limitations.

OBJECTIVE: To evaluate the effectiveness of long-term, personalized, supervised exercise therapy on functional ability compared with usual care in people with axial spondyloarthritis (axSpA) and severe functional limitations. METHODS: Participants were randomly 1:1 assigned to the intervention(maximal 64 sessions, with 14 additional optional sessions of supervised active exercise therapy(e.g. aerobic and muscle strengthening) with individualized goal-setting, education and self-management regarding physical activity) or usual care(care determined by clinician(s) and participants themselves). Primary end point was the change in the Patient-Specific Complaints activity ranked 1 (PSC1 (0-10)) at 52 weeks. Secondary endpoints were the PSC activities ranked 2 and 3, the Bath Ankylosing Spondylitis Functional Index, 6-min walk test, Patient Reported Outcome Measurement Information System-Physical Function-10 and the Short Form-36 Physical and Mental Component Summary Score (SF-36 PCS and MCS). Statistical comparisons comprised independent student t-tests and linear mixed models, based on intention-to-treat. RESULTS: 214 participants(49% female, age 52 (SD 12) years), were randomized to the intervention (n = 110) or usual care (N = 104) group. In the intervention group 93% started treatment, using on average 40.5 sessions (SD 15.1). At 52 weeks, the difference in change in PSC1 between groups favored the intervention group (mean difference [95% CI]; -1.8 [-2.4 to -1.2]). additionally, all secondary outcomes, except the SF-36 MSC, showed significantly greater improvements in the intervention group with effect sizes ranging from 0.4-0.7. CONCLUSION: Long-term, supervised exercise therapy proved more effective than usual care in improving functional disability and physical quality of life in people with axSpA and severe functional limitations. CLINICAL TRIAL REGISTER NUMBER: Netherlands Trial Register NL8238, included in the International Clinical Trial Registry Platform (ICTRP) (https://trialsearch.who.int/Trial2.aspx?TrialID=NL8238).

Atlas for the CT Syndesmophyte Score (CTSS) in patients with axial spondyloarthritis.

BACKGROUND: The Computed Tomography Syndesmophyte Score (CTSS) was developed as a reliable and sensitive tool to assess syndesmophytes in low-dose CT images of the entire spine in patients with axial spondyloarthritis (axSpA). The original paper provided sparce examples of the CTSS grades. OBJECTIVES: Provide an atlas tailored to assist readers in understanding and employing the CTSS method. METHODS: In this paper, illustrations of the different grades and views of the CTSS are presented. CTSS is used to measure bone formation in the spine of patients with axial spondyloarthritis (axSpA), in the form of syndesmophytes. In both the sagittal and coronal planes, syndesmophytes can be graded from 0 to 3 over 23 vertebral units starting at C2 and ending at S1. The CTSS ranges from 0 (absence of axSpA-related syndesmophytes) to 552 (total ankylosis of the spine). RESULTS: The current atlas contains low-dose CT images of the spine without lesions (for reference) and all grades of syndesmophytes in different planes used in the CTSS. Examples are arranged per spinal segment (cervical, thoracic and lumbar). CONCLUSIONS: These images can be used to assist any reader in the assessment of syndesmophytes on (low-dose) CT in patients with axSpA.

Can rheumatologists unequivocally diagnose axial spondyloarthritis in patients with chronic back pain of less than 2 years duration? Primary outcome of the 2-year SPondyloArthritis Caught Early (SPACE) cohort.

OBJECTIVES: To investigate the prevalence of axial spondyloarthritis (axSpA) in patients with chronic back pain (CBP) of less than 2 years (2y) duration referred to the rheumatologist, the development of diagnosis over time, and patient characteristics of those developing definite (d-)axSpA over 2y. METHODS: We analysed the 2y data from SPondyloArthritis Caught Early, a European cohort of patients (<45 years) with CBP (≥3 months, ≤2y) of unknown origin. The diagnostic workup comprised evaluation of clinical SpA features, acute phase reactants, HLA-B27, radiographs and MRI (sacroiliac joints and spine), with repeated assessments. At each visit (baseline, 3 months, 1y and 2y), rheumatologists reported a diagnosis of axSpA or non-axSpA with level of confidence (LoC; 0-not confident at all to 10-very confident). MAIN OUTCOME: axSpA diagnosis with LoC≥7 (d-axSpA) at 2y. RESULTS: In 552 patients with CBP, d-axSpA was diagnosed in 175 (32%) at baseline and 165 (30%) at 2y. Baseline diagnosis remained rather stable: at 2y, baseline d-axSpA was revised in 5% of patients, while 8% 'gained' d-axSpA. Diagnostic uncertainty persisted in 30%. HLA-B27+ and baseline sacroiliitis imaging discriminated best 2y-d-axSpA versus 2y-d-non-axSpA patients. Good response to non-steroidal anti-inflammatory drugs and MRI-sacroiliitis most frequently developed over follow-up in patients with a new d-axSpA diagnosis. Of the patients who developed MRI-sacroiliitis, 7/8 were HLA-B27+ and 5/8 male. CONCLUSION: A diagnosis of d-axSpA can be reliably made in nearly one-third of patients with CBP referred to the rheumatologist, but diagnostic uncertainty may persist in 5%-30% after 2y. Repeated assessments yield is modest, but repeating MRI may be worthwhile in male HLA-B27+ patients.

Goodbye to the term 'ankylosing spondylitis', hello 'axial spondyloarthritis': time to embrace the ASAS-defined nomenclature.

Ankylosing spondylitis (AS) is the historic term used for decades for the HLA-B27-associated inflammatory disease affecting mainly the sacroiliac joints (SIJ) and spine. Classification criteria for AS have radiographic sacroiliitis as a dominant characteristic. However, with the availability of MRI of SIJ, it could be demonstrated that the disease starts long before definite SIJ changes become visible on radiographs. The Assessment of SpondyloArthritis international Society, representing a worldwide group of experts reached consensus on changes in the nomenclature pertaining to axial spondyloarthritis (axSpA), such as the terminology of diagnosis and of assessment of disease activity tools. These are important changes in the field, as experts in axSpA are now in agreement that the term axSpA is the overall term for the disease. A further differentiation, of which radiographic versus non-radiographic is only one aspect, may be relevant for research purposes. Another important decision was that the terms AS and radiographic axSpA (r-axSpA) can be used interchangeably, but that the preferred term is r-axSpA. Based on the decision that axSpA is the correct terminology, a proposal was made to officially change the meaning of the ASDAS acronym to 'Axial Spondyloarthritis Disease Activity Score'. In addition, for simplification it was proposed that the term ASDAS (instead of ASDAS-CRP) should be preferred and applied to the ASDAS calculated with C reactive protein (CRP). It is hoped that these changes will be used consequently for education, in textbooks, manuscripts and presentations.

Challenges in the diagnosis of axial spondyloarthritis.

With back pain as one of the most common complaints in the population and with no single disease feature with sufficient sensitivity and specificity to diagnose axial spondyloarthritis (axSpA) on its own, diagnosing axSpA can be challenging. In this article, we discuss clinical, laboratory, and imaging spondyloarthritis features that can be used in diagnosis and explain the general principles underlying an axSpA diagnosis. Moreover, we discuss three pitfalls to avoid when diagnosing axSpA: i) using classification criteria as diagnostic criteria, ii) making a diagnosis by simple counting of spondyloarthritis features, and iii) over-reliance on imaging findings. Finally, we have some advice on how to build diagnostic skills and discuss new developments that may help facilitate the diagnosis of axSpA in the future.

Do fatty lesions explain the effect of inflammation on new syndesmophytes in patients with radiographic axial spondyloarthritis? Results from the SIAS cohort and ASSERT trial.

OBJECTIVES: To determine how much of the effect of vertebral corner inflammation on development of syndesmophytes is explained by vertebral corner fat deposition. METHODS: Patients with radiographic axial spondyloarthritis (r-axSpA) from the SIAS (Sensitive Imaging in Ankylosing Spondylitis) cohort and ASSERT (Ankylosing Spondylitis Study for the Evaluation of Recombinant Infliximab Therapy) trial were assessed at T0, T1 (SIAS: 1 year; ASSERT: 24 weeks) and T2 (2 years). Syndesmophytes assessed in each vertebral corner by whole spine low-dose CT (SIAS) or spinal radiographs (ASSERT) at T0 and T2 were considered present if seen by two of two readers. Inflammation (T0) and fat deposition (T0 and T1) on MRI were present if seen by ≥2 of 3 readers (SIAS) or 2 of 2 readers (ASSERT). Vertebral corners showing fat deposition or a syndesmophyte at baseline were ignored. Mediation analysis was applied to determine what proportion of the total effect of inflammation on syndesmophyte formation could be explained via the path of intermediate fat deposition. RESULTS: Forty-nine SIAS patients (with 2667 vertebral corners) and 168 ASSERT patients (with 2918 vertebral corners) were analysed. The presence of inflammation at T0 increased the probability of a new syndesmophyte in the same vertebral corner at T2 by 9.3%. Of this total effect, 0.2% (2% (0.2 of 9.3) of the total effect) went via intermediate new fat deposition. In ASSERT, the total effect was 7.3%, of which 0.8% (10% of the total effect) went via new fat deposition. CONCLUSION: In r-axSpA, vertebral corner inflammation may lead to syndesmophyte formation but in a minority of cases via visible fat deposition.

The value of correctly diagnosing axial spondyloarthritis for patients and society.

OBJECTIVE: To demonstrate the value of diagnosing axSpA, by comparing health and costs associated with available diagnostic algorithms and perfect diagnosis. METHODS: Using data from SPACE and other cohorts, a model was developed to estimate health (quality-adjusted life-years, QALYs) and costs (healthcare consumption and work productivity losses) of different diagnostic algorithms for axSpA amongst patients with low back pain referred to a rheumatologist, over a 60-year horizon. The model combined a decision-tree (diagnosis) with a state-transition model (treatment). The three algorithms (Berlin [BER, highest specificity], Modification 1 [M1; less strict inflammatory back pain (IBP) criterion] and Modification 2 [M2; IBP not mandatory as entry criterion, highest sensitivity]) were compared. Changes in sensitivity/specificity were explored and the value of perfect diagnosis was investigated. RESULTS: For each correctly diagnosed axSpA patient, up to 4.7 QALYs and €60,000 could be gained/saved, considering a societal perspective. Algorithm M2 resulted in more health and lower costs per patient (24.23 QALYs; €157,469), compared to BER (23.96 QALYs; €159,423) and M1 (24.15 QALYs; €158,417). Hypothetical improvements in M2 sensitivity resulted in slightly more value compared to improvements in specificity. Perfect diagnosis can cost €7,500 per patient and still provide enough value. CONCLUSION: Correct diagnosis of axSpA results in substantial health and cost benefits for patients and society. Not requiring IBP as mandatory for diagnosis of axSpA (algorithm M2) provides more value and would be preferable. A considerably more expensive diagnostic algorithm with better accuracy than M2 would still be considered good value for money.

Spondyloarthritis mass cytometry immuno-monitoring: a proof of concept study in the tight-control and treat-to target TiCoSpA trial.

OBJECTIVE: Mass cytometry (MC) immunoprofiling allows high-parameter phenotyping of immune cells. We set to investigate the potential of MC immuno-monitoring of axial spondyloarthritis (axSpA) patients enrolled in the Tight Control SpondyloArthritis (TiCoSpA) trial. METHODS: Fresh, longitudinal PBMCs samples (baseline, 24, and 48 weeks) from 9 early, untreated axSpA patients and 7 HLA-B27+ controls were analyzed using a 35-marker panel. Data were subjected to HSNE dimension reduction and Gaussian mean shift clustering (Cytosplore), followed by Cytofast analysis. Linear discriminant analyzer (LDA), based on initial HSNE clustering, was applied onto week 24 and 48 samples. RESULTS: Unsupervised analysis yielded a clear separation of baseline patients and controls including a significant difference in 9 T cell, B cell, and monocyte clusters (cl), indicating disrupted immune homeostasis. Decrease in disease activity (ASDAS score; median 1.7, range 0.6-3.2) from baseline to week 48 matched significant changes over time in five clusters: cl10 CD4 Tnai cells median 4.7 to 0.02%, cl37 CD4 Tem cells median 0.13 to 8.28%, cl8 CD4 Tcm cells median 3.2 to 0.02%, cl39 B cells median 0.12 to 2.56%, and cl5 CD38+ B cells median 2.52 to 0.64% (all p<0.05). CONCLUSIONS: Our results showed that a decrease in disease activity in axSpA coincided with normalization of peripheral T- and B-cell frequency abnormalities. This proof of concept study shows the value of MC immuno-monitoring in clinical trials and longitudinal studies in axSpA. MC immunophenotyping on a larger, multi-center scale is likely to provide crucial new insights in the effect of anti-inflammatory treatment and thereby the pathogenesis of inflammatory rheumatic diseases. Key Points • Longitudinal immuno-monitoring of axSpA patients through mass cytometry indicates that normalization of immune cell compartments coincides with decrease in disease activity. • Our proof of concept study confirms the value of immune-monitoring utilizing mass cytometry.

ASAS consensus definition of early axial spondyloarthritis.

OBJECTIVES: To develop a consensual definition for the term 'early axial spondyloarthritis-axSpA'-and 'early peripheral spondyloarthritis-pSpA'. METHODS: The ASAS (Assessment of SpondyloArthritis international Society-Spondyloarthritis EARly definition) steering committee convened an international working group (WG). Five consecutive steps were followed: (1) systematic literature review (SLR); (2) discussion of SLR results within the WG and ASAS community; (3) a three-round Delphi survey inviting all ASAS members to select the items that should be considered for the definition; (4) presentation of Delphi results to the WG and ASAS community and (5) ASAS voting and endorsement (2023 annual meeting). RESULTS: Following the SLR, consensus was to proceed with an expert-based definition for early axSpA (81% in favour) but not for pSpA (54% against). Importantly, early axSpA should be based on symptom duration taking solely axial symptoms into account. 151-164 ASAS members participated in the Delphi surveys. Consensus was achieved for considering the following items within early axSpA definition: duration of symptoms ≤2 years; axial symptoms defined as cervical/thoracic/back/buttock pain or morning stiffness; regardless of the presence/absence of radiographic damage. The WG agreed that in patients with a diagnosis of axSpA 'early axSpA' should be defined as a duration of ≤2 years of axial symptoms. Axial symptoms should include spinal/buttock pain or morning stiffness and should be considered by a rheumatologist as related to axSpA. The ASAS community endorsed this proposal (88% in favour). CONCLUSIONS: Early axSpA has newly been defined, based on expert consensus. This ASAS definition should be adopted in research studies addressing early axSpA.

Good construct validity of the CT Syndesmophyte Score (CTSS) in patients with radiographic axial spondyloarthritis.

OBJECTIVES: To assess construct validity of the CT Syndesmophyte Score (CTSS) for the measurement of structural spinal damage in patients with radiographic axial spondyloarthritis. METHODS: Low-dose CT and conventional radiography (CR) were performed at baseline and 2 years. CT was assessed with CTSS by two readers and CR with modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) by three readers. Two hypotheses were tested: (1) syndesmophytes scored with CTSS are also detected with mSASSS at baseline or 2 years later; (2) CTSS is non-inferior to mSASSS in correlations with spinal mobility measures. Presence of a syndesmophyte was determined per reader per corner for all anterior cervical and lumbar corners on CT at baseline and CR at baseline and 2 years. Correlations of CTSS and mSASSS with six spinal/hip mobility measurements plus Bath Ankylosing Spondylitis Metrology Index (BASMI) were tested. RESULTS: Data from 48 patients (85% male, 85% HLA-B27+, mean age 48 years) were available for hypothesis 1 and 41/48 were available for hypothesis 2. At baseline, syndesmophytes were scored with CTSS in 348 (reader 1, 38%) and 327 (reader 2, 36%) corners out of 917. Of these, depending on reader pairs, 62%-79% were also seen on CR at baseline or after 2 years. CTSS correlated well (rs 0.46-0.73), and with higher correlation coefficients than mSASSS (rs 0.34-0.64), with all spinal mobility measures and BASMI. CONCLUSIONS: The good agreement between syndesmophytes detected by CTSS and mSASSS and the strong correlation of CTSS with spinal mobility support the construct validity of the CTSS.

Inflammation, bone loss and 2-year bone formation at the same vertebra in axial spondyloarthritis: a multilevel MRI and low-dose CT analysis.

OBJECTIVE: To investigate whether in radiographic axial spondyloarthritis (r-axSpA) inflammation is associated with lower trabecular bone density (TBD), and subsequently, if a lower TBD increases the likelihood of 2-year bone formation at the same vertebra. METHODS: Whole spine (C3-L5) data from patients included in the multicentre 2-year Sensitive Imaging in Ankylosing Spondylitis cohort was used. Two readers measured baseline TBD by Hounsfield units (HU) on low-dose CT (ldCT). Baseline MRI bone marrow oedema (BME) status scores and ldCT syndesmophyte formation and/or growth change-from-baseline scores were assessed by three and two readers, respectively. Average of readers' continuous measurements or readers' agreement in binary scores generated within the same vertebra (1-present in ≥1 quadrant/0-absent in all quadrants) were used. Multilevel generalised estimating equations models were used, the unit of analysis being the vertebra. RESULTS: In 50 patients with r-axSpA, TBD HU decreased from cranial to caudal vertebrae. Baseline MRI-BME was present in 300/985 (30%) and syndesmophytes in 588/910 (65%) vertebrae, both most prevalent at thoracolumbar region. Syndesmophyte formation or growth was observed in 18% of at-risk vertebrae (124/691). A significant confounder-adjusted association was found between inflammation and lower TBD (regression coefficient=-51; 95% CI-63 to -39). TBD was not associated with 2-year syndesmophyte formation or growth (adjusted OR 1.00; 95% CI 0.99 to 1.00). CONCLUSION: In r-axSpA, while vertebral inflammation was associated with lower vertebral TBD, lower vertebral TBD itself did not increase the risk for new bone formation at the same vertebra. In preventing syndesmophyte progression, targeting local inflammation seems more important than targeting vertebral trabecular bone loss.

Hounsfield Units measured in low dose CT reliably assess vertebral trabecular bone density changes over two years in axial spondyloarthritis.

OBJECTIVES: To describe low dose Computed Tomography (ldCT) Hounsfield Units (HU) two-year change-from-baseline values (expressing trabecular bone density changes) and analyse their inter-reader reliability per vertebra in radiographic axial spondyloarthritis (r-axSpA). METHODS: We used 49 patients with r-axSpA from the multicentre two-year Sensitive Imaging in Ankylosing Spondylitis (SIAS) study. LdCT HU were independently measured by two trained readers at baseline and two years. Mean (standard deviation, SD) for the change-from-baseline HU values were provided per vertebra by reader. Intraclass correlation coefficients (ICC; absolute agreement, two-way random effect), Bland-Altman plots and smallest detectable change (SDC) were obtained. Percentages of vertebrae in which readers agreed on the direction of change and on change >|SDC| were computed. RESULTS: Overall, 1,053 (98% of all possible) vertebrae were assessed by each reader both at baseline and two years. Over two years, HU mean change values varied from -23 to 28 and 29 for reader 1 and 2, respectively. Inter-reader reliability of the two-year change-from-baseline values per vertebra was excellent: ICC:0.91-0.99; SDC:6-10; Bland-Altman plots were homoscedastic, with negligible systematic error between readers. Readers agreed on the direction of change in 88-96% and on change >|SDC| in 58-94% of vertebrae, per vertebral level, from C3 to L5. Overall, similar results were obtained across all vertebrae. CONCLUSION: LdCT measurement of HU is a reliable method to assess two-year changes in trabecular bone density at each vertebra from C3-L5. Being reliable across all vertebrae, this methodology can aid the study of trabecular bone density changes over time in r-axSpA, a disease affecting the whole spine.

ASAS-EULAR recommendations for the management of axial spondyloarthritis: 2022 update.

OBJECTIVES: To update the Assessment of SpondyloArthritis international Society (ASAS)-EULAR recommendations for the management of axial spondyloarthritis (axSpA). METHODS: Following the EULAR Standardised Operating Procedures, two systematic literature reviews were conducted on non-pharmacological and pharmacological treatment of axSpA. In a task force meeting, the evidence was presented, discussed, and overarching principles and recommendations were updated, followed by voting. RESULTS: Five overarching principles and 15 recommendations with a focus on personalised medicine were agreed: eight remained unchanged from the previous recommendations; three with minor edits on nomenclature; two with relevant updates (#9, 12); two newly formulated (#10, 11). The first five recommendations focus on treatment target and monitoring, non-pharmacological management and non-steroidal anti-inflammatory drugs (NSAIDs) as first-choice pharmacological treatment. Recommendations 6-8 deal with analgesics and discourage long-term glucocorticoids and conventional synthetic disease-modifying antirheumatic drugs (DMARDs) for pure axial involvement. Recommendation 9 describes the indication of biological DMARDs (bDMARDs, that is, tumour necrosis factor inhibitors (TNFi), interleukin-17 inhibitors (IL-17i)) and targeted synthetic DMARDs (tsDMARDs, ie, Janus kinase inhibitors) for patients who have Ankylosing Spondylitis Disease Activity Score ≥2.1 and failed ≥2 NSAIDs and also have either elevated C reactive protein, MRI inflammation of sacroiliac joints or radiographic sacroiliitis. Current practice is to start a TNFi or IL-17i. Recommendation 10 addresses extramusculoskeletal manifestations with TNF monoclonal antibodies preferred for recurrent uveitis or inflammatory bowel disease, and IL-17i for significant psoriasis. Treatment failure should prompt re-evaluation of the diagnosis and consideration of the presence of comorbidities (#11). If active axSpA is confirmed, switching to another b/tsDMARD is recommended (#12). Tapering, rather than immediate discontinuation of a bDMARD, can be considered in patients in sustained remission (#13). The last recommendations (#14, 15) deal with surgery and spinal fractures. CONCLUSIONS: The 2022 ASAS-EULAR recommendations provide up-to-date guidance on the management of patients with axSpA.

Role of vertebral corner inflammation and fat deposition on MRI on syndesmophyte development detected on whole spine low-dose CT scan in radiographic axial spondyloarthritis.

OBJECTIVES: To investigate the associations between MRI detected vertebral corner inflammation (VCI) and vertebral corner fat deposition (VCFD) on whole spine low-dose CT scan (ldCT) detected syndesmophyte formation and growth. METHODS: Patients from the Sensitive Imaging in Ankylosing Spondylitis cohort underwent MRI (baseline, 1 year and 2 years) and ldCT (baseline and 2 years). MR images were scored by three readers for VCI and VCFD, MRI patterns were defined by presence of VCI and/or VCFD over 2 years. LdCT images were scored by two central readers for presence and size of syndesmophytes and change was calculated for new or new/grown syndesmophytes. Multilevel generalised estimated equations were used to test the associations between VCI and VCFD and syndesmophyte development. RESULTS: Fifty radiographic patients with axial spondyloarthritis were included (mean age 49 years, 86% male, 78% HLA-B27+). Absence of both VCI and VCFD protected against syndesmophyte development (ORs 0.36-0.37). Presence of VCI and/or VCFD increased the risk of syndesmophyte development (ORs 1.73-2.60). Out of all corners with a new or new/grown syndesmophyte, 47% of corners according to reader 1 and 44% according to reader 2 had neither VCI nor VCFD preceding the bone formation. CONCLUSIONS: VCI and VCFD were positively associated with syndesmophyte development. This has been shown for the first time for syndesmophytes detected on ldCT and also in the thoracic spine. However, almost half of all bone formation occurred in corners without VCI or VCFD, suggesting the presence of these lesions in yearly MRIs does not fully clarify the development of syndesmophytes.

Low-dose CT hounsfield units: a reliable methodology for assessing vertebral bone density in radiographic axial spondyloarthritis.

OBJECTIVE: Studying vertebral bone loss in radiographic axial spondyloarthritis (r-axSpA) has been challenging due to ectopic bone formation. We cross-sectionally analysed low-dose CT (ldCT) trabecular bone density Hounsfield units (HU) measurements and calculated inter-reader reliability at the vertebral level in patients with r-axSpA. METHODS: LdCT scans of 50 patients with r-axSpA from the sensitive imaging in ankylosing spondylitis study, a multicentre 2-year prospective cohort were included. Trabecular bone HU taken from a region of interest at the centre of each vertebra (C3-L5) were independently assessed by two trained readers. HU mean (SD), and range were provided at the vertebral level, for each reader and centre separately. Inter-reader reliability and agreement were assessed using intraclass correlation coefficients (ICC; single measurements, absolute agreement, two-way mixed effects models); smallest detectable difference and Bland-Altman plots. RESULTS: Overall, 1100 vertebrae were assessed by each reader. HU values decreased from cranial to caudal vertebrae. For readers 1 and 2 respectively, the highest mean (SD) HU value was obtained at C3 (354(106) and 355(108)), and the lowest at L3 (153(65) and 150 (65)). Inter-reader reliability was excellent (ICC(2,1):0.89 to 1.00). SDD varied from 4 to 8. For most vertebrae, reader 1 scored somewhat higher than reader 2 (mean difference of scores ranging from -0.6 to 2.9 HU). Bland-Altman plots showed homoscedasticity. CONCLUSION: LdCT measurement of HU is a feasible method to assess vertebral bone density in r-axSpA with excellent inter-reader reliability from C3 to L5. These results warrant further validation and longitudinal assessment of reliability.

Geographical prevalence of family history in patients with axial spondyloarthritis and its association with HLA-B27 in the ASAS-PerSpA study.

BACKGROUND: A positive family history (PFH) of spondyloarthritis (SpA) consists of five SpA-related entities, of which a PFH of axial spondyloarthritis (axSpA) is most common in European patients with axSpA. Moreover, a PFH of axSpA is associated with human leucocyte antigen B27 (HLA-B27) positivity in these patients. It is unknown if this holds true in patients with axSpA in other parts of the world. OBJECTIVE: To investigate the geographical prevalence of a PFH of SpA and its association with HLA-B27 positivity in patients with axSpA worldwide. METHODS: Cross-sectional analyses included patients from the ASAS peripheral involvement in Spondyloarthritis (PerSpA) study from 24 countries worldwide with an axSpA diagnosis, known HLA-B27 status and family history. Logistic regression models were built to assess the effect of HLA-B27 status on the occurrence of PFH. This was repeated for each of the five SpA entities in a PFH. RESULTS: Among 2048 patients, axSpA was the most common SpA entity in a PFH in all geographical regions (Asia 28%, Europe and North America 27%, Latin America 20%, Middle East and North Africa 41%). A PFH of axSpA was associated with HLA-B27 positivity in Asia (OR 4.19), Europe and North America (OR 2.09) and Latin America (OR 3.95), but not in the Middle East and North Africa (OR 0.98), which has a lower prevalence of HLA-B27 positivity. A PFH of other SpA entities was less prevalent and not consistently associated with HLA-B27 positivity. CONCLUSION: In patients with axSpA worldwide, axSpA was consistently the most common SpA entity in a family history and was associated with HLA-B27 positivity in all geographical regions but one.

Associations between syndesmophytes and facet joint ankylosis in radiographic axial spondyloarthritis patients on low-dose CT over 2 years.

OBJECTIVES: In radiographic axial spondyloarthritis (r-axSpA), spinal damage manifests as syndesmophytes and facet joint ankylosis (FJA). We evaluated whether the presence of one lesion increased the risk of the other lesion. METHODS: Patients with r-axSpA underwent low-dose CT (ldCT) and MRI of the whole spine at baseline and 2 years. On ldCT, vertebrae were scored for presence and size of syndesmophytes; facet joints were assessed for ankylosis. MR images were assessed for inflammation. Two hypotheses were tested: (i) presence of FJA is associated with new syndesmophyte(s) on the same vertebral unit (VU) 2 years later, and (ii) presence of bridging syndesmophyte(s) is associated with new FJA on the same VU 2 years later. Two generalized estimating equations models were tested per hypothesis using increase of FJA/syndesmophytes (model A) or presence of FJA/syndesmophytes (model B) as outcome, adjusted for inflammation at baseline. Secondary analyses tested the hypotheses with outcomes on adjacent VUs and dose-response effects. RESULTS: Fifty-one patients were included (mean age 49, 84% male, 82% HLA-B27+). Baseline bridging syndesmophytes occurred more often (range: 10-60% per VU) than FJA (range: 8-36%). Odds ratios (ORs) (95% CI) for presence of bridging syndesmophytes on development of FJA were 3.55 (2.03, 6.21) for model A and 3.30 (2.14, 5.09) for model B. ORs for presence of baseline FJA on new syndesmophytes were 1.87 (1.20, 2.92) for model A and 1.69 (0.88, 3.22) for model B. Secondary analyses yielded positive ORs for both hypotheses. CONCLUSIONS: Bone formation in vertebrae and in facet joints influence each other's occurrence, with the effect of syndesmophytes being larger than that of FJA.

Measuring quality of life of patients with axial spondyloarthritis for economic evaluation.

OBJECTIVES: To estimate the relationship between EQ5D (three levels, UK version) and the Ankylosing Spondylitis Disease Activity Score (ASDAS) for use in the economic evaluation of health technologies for people with axial spondyloarthritis (axSpA). To compare against the relationship with the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). METHODS: An electronic, prospective, Portuguese, nationwide, rheumatic disease register (Reuma.pt) provided data on 1140 patients (5483 observations) with a confirmed diagnosis of axSpA. We estimated models of EQ5D as a function of ASDAS, alone or in combination with measures of functional impairment, using bespoke mixture models which reflect the complex distributional features of EQ5D. The SPondyloArthritis Caught Early cohort provided data from 344 patients (1405 observations) in four European countries and was used for validation. A previously published model of BASDAI/Bath Ankylosing Spondylitis Functional Index (BASFI) was also used to generate predicted EQ5D scores and model performance compared. RESULTS: A non-linear relationship exists between EQ5D from ASDAS. The final model included ASDAS, ASDAS squared, age and age squared and demonstrated close fit in both datasets except where data were sparse for patients with very high levels of disease activity (ASDAS >4). This finding held in the validation dataset. Models that included BASFI improved model fit. The ASDAS based models fit the data marginally less well than models using BASDAI. CONCLUSIONS: Mapping models linking ASDAS to EQ5D allow results from clinical studies to be used in economic evaluation of health technologies with confidence. There is some loss of information compared with BASDAI but this has only a marginal impact.