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Objective To compare spinal symptoms and spinal/hip mobility at baseline and 2 years in early axial spondyloarthritis (axSpA) and non-axSpA chronic back pain (BP) patients.Methods Baseline and 2 years data of the SPondyloarthritis Caught Early cohort were analysed. Outcomes assessed: overall BP, BP at night, morning stiffness (MS) intensity, MS duration, occiput-to-wall distance (OWD), cervical rotation, chest expansion, lateral spinal flexion (LSF), modified Schober test (mSchober), intermalleolar distance (IMD) and Bath Ankylosing Spondylitis Metrology Index (BASMI). Linear or zero-inflated negative binomial regression was used to compare 2 years outcomes between groups (adjusting for baseline value, sex, age and use of non-steroidal anti-inflammatory drugs).Results There were 294 axSpA and 123 non-axSpA patients (mean symptom duration: 13 months). At baseline, non-axSpA patients had worse symptoms and mobility, except OWD (eg, mean(SD): BP at night 3.6 (2.9) axSpA vs 4.6 (2.7) non-axSpA; OWD 0.5 (1.2) vs 0.1 (0.7)). After 2 years, all symptoms and cervical rotation significantly improved in both groups, but LSF and mSchober only in axSpA. In multivariable analyses, axSpA was associated with larger improvements in BP at night (β (95% CI): −0.85 (−1.47; −0.23)), mSchober (0.26 (0.03; 0.50)), IMD (4.86 (1.93; 7.80)) and BASMI (−0.24 (−0.41; −0.08)), and with lower likelihood of a normal OWD (OR (95% CI): 0.09 (0.01; 0.83)).Conclusion Over 2 years, all spinal symptoms and some mobility measures improved in both groups, but impairments remained prevalent (particularly in non-axSpA). Nevertheless, axSpA was associated with larger improvements in BP at night, mSchober, IMD and BASMI, but with more OWD impairment.

Objectives To follow up four previously identified classes ‘pure axial spondyloarthritis’ (axSpA) (‘axial’), ‘axSpA with peripheral signs’ (‘inflammatory back pain+peripheral’), ‘axSpA at risk’ and ‘no spondyloarthritis’ (‘no SpA’). They reflect the expert-opinion-free construct or ‘Gestalt’ of chronic back pain suspicious of axSpA. The aim was to assess participants’ transitions between these classes over time.Methods Participants with chronic back pain of ≤2 years duration, suspicious of axSpA from the SPondyloArthritis Caught Early cohort were analysed. Latent class (LCA) and latent transition analysis (LTA) using clinical, laboratory and imaging data at baseline and 2 years were calculated. Conditional and marginal probabilities were obtained, reflecting the probability of a spondyloarthritis feature in a class and the probability of the participant’s class membership, respectively. Transitional probabilities were extracted revealing potential switches across classes. The analyses were performed in all participants using imputations for missing data and in participants with full data at baseline and 2 years.Results Baseline and 2 years LCA models were constructed for 702 participants, resulting in the same four-class model as previously described. LTA revealed only a 3% transition from the ‘no SpA’ to the ‘at-risk’ class from baseline to 2 years with all other participants remaining in their initially assigned class. Sensitivity analysis on 384 participants with complete data at both baseline and 2 years showed similar results, underlining the model’s robustness.Conclusions Transitions between the four classes over 2 years were basically inexistent, highlighting the unlikelihood of developing new class-defining features of axSpA after an initial clinical workup.

Objective To evaluate the sensitivity to change in structural imaging outcomes over 10 years of follow-up in patients with axial spondyloarthritis (axSpA).Methods Patients with axSpA from the Devenir des Spondyloarthropathies Indifferénciées Récentes cohort were included. Radiographs and MRIs of the sacroiliac joints (SIJ) and spine were obtained at baseline and at 1, 2, 5 and 10 years. The yearly rate of change of each structural outcome was analysed using generalised estimating equation models, including all patients with ≥1 score from ≥1 reader from ≥1 reading wave, using the time (years) as an explanatory variable and adjusting for reader and wave. All outcomes were standardised, and the relative standardised rate of change was calculated (ie, the standardised rate of an outcome divided by the rate of a reference outcome).Results A total of 659 patients (46% males and mean age 33.6 years) were included. The most sensitive outcome to change in the SIJ (both MRI and radiographs) was the presence of ≥3 fatty lesions at a specific timepoint, with a relative standardised rate of change per year of 5.28 using the modified New York criteria as reference.Similarly, the most sensitive to change (in both MRI and radiographs) outcome in the spine was the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS; relative standardised yearly change 1.76) using ≥1 syndesmophyte as reference.Conclusion MRI structural outcomes in the SIJ (ie, fatty lesions) are more sensitive to change than radiographic outcomes. Conversely, the mSASSS remains the most sensitive method, even when compared with MRI of the spine.

Background The Assessment of SpondyloArthritis international Society-European Alliance of Associations for Rheumatology recommendations for axial spondyloarthritis (axSpA) management include patient assessment for biological disease-modifying antirheumatic drug (bDMARD) treatment response after at least 12 weeks of treatment. The current treat-to-target strategy for axSpA is to achieve inactive disease (ID; Axial Spondyloarthritis Disease Activity Score (ASDAS)

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.

Objective To assess how achievement of increasingly stringent clinical response criteria and disease activity states at week 52 translate into changes in core domains in patients with non-radiographic (nr-) and radiographic (r-) axial spondyloarthritis (axSpA).Methods Patients in BE MOBILE 1 and 2 achieving different levels of response or disease activity (Assessment of SpondyloArthritis International Society (ASAS) and Ankylosing Spondylitis Disease Activity Score (ASDAS) response criteria, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI50)) at week 52 were pooled, regardless of treatment arm. Associations between achievement of these endpoints and change from baseline (CfB) in patient-reported outcomes (PROs) measuring core axSpA domains, including pain, fatigue, physical function, overall functioning and health, and work and employment, were assessed.Results Achievement of increasingly stringent clinical efficacy endpoints at week 52 was generally associated with sequentially greater improvements from baseline in all PROs. Patients with nr-axSpA achieving ASAS40 demonstrated greater improvements (CfB) than patients who did not achieve ASAS40 but did achieve ASAS20, in total spinal pain (−5.3 vs −2.8, respectively), Functional Assessment of Chronic Illness-Fatigue subscale (12.7 vs 6.7), Bath Ankylosing Spondylitis Function Index (−3.9 vs −1.8), European Quality of Life 5-Dimension 3-Level Version (0.30 vs 0.16), Work Productivity and Activity Impairment-axSpA presenteeism (−35.4 vs −15.9), overall work impairment (−36.5 vs −12.9), activity impairment (−39.0 vs −21.0) and sleep (9.0 vs 3.9). Results were similar for ASDAS and BASDAI50. Similar amplitudes of improvement were observed between patients with nr-axSpA and r-axSpA.Conclusions Patients treated with bimekizumab across the full axSpA disease spectrum, who achieved increasingly stringent clinical response criteria and lower disease activity at week 52, reported larger improvements in core axSpA domains.

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.

Abstract Background CT Severity Score (CT-SS) can be used to assess the extent of severe coronavirus disease 19 (COVID-19) pneumonia. Follow-up CT-SS in patients surviving COVID-19-associated hyperinflammation and its correlation with respiratory parameters remains unknown. This study aims to assess the association between CT-SS and respiratory outcomes, both in hospital and at three months after hospitalization. Methods Patients from the COVID-19 High-intensity Immunosuppression in Cytokine storm Syndrome (CHIC) study surviving hospitalization due to COVID-19 associated hyperinflammation were invited for follow-up assessment at three months after hospitalization. Results of CT-SS three months after hospitalization were compared with CT-SS at hospital admission. CT-SS at admission and at 3-months were correlated with respiratory status during hospitalization and with patient reported outcomes as well as pulmonary- and exercise function tests at 3-months after hospitalization. Results A total of 113 patients were included. Mean CT-SS decreased by 40.4% (SD 27.6) in three months (P 80%pred vs. 14.3 (3.2) in those with DLCO

Objective The objective of this study is to build a structural model visualising and quantifying the interrelationships of different disease outcomes with the Assessment of SpondyloArthritis International Society Health Index (ASAS HI) in patients with axial spondyloarthritis (axSpA).Methods Cross-sectional data collected at month 72 of the Devenir des Spondylarthropathies Indifferénciées Récentes cohort was analysed. Combining prior knowledge and observed data, probabilistic Bayesian network modelling was used to study how the interplay of different disease outcomes affects the ASAS HI, which measures disease-specific overall functioning and health. Disease outcomes comprised, among others, the Ankylosing Spondylitis (AS) Disease Activity Score (ASDAS) and the Bath AS Functional Index (BASFI).Results Data of 384 patients were analysed. The obtained structure suggests that ASAS HI is determined by both patient-reported physical function (BASFI) and disease activity (ASDAS). The parameters of the structural model show that an increase of ASDAS or BASFI by 1 unit corresponds to an increase of ASAS HI by 0.70 or 1.25 units, respectively. Moreover, the model suggests that disease activity has an indirect impact on ASAS HI via BASFI. No relationship between spinal mobility or structural damage and ASAS HI was found.Conclusions This is the first structural model developed to better understand the construct and the interplay between clinically relevant outcomes related to ASAS HI in axSpA patients. It shows that disease activity and physical function have a strong impact on ASAS HI, confirming it to be a valid construct of overall functioning and health in axSpA patients.

Objectives The objective of this study is to evaluate whether there are differences in the long-term prognosis across various phenotypes of early arthritis (EA).Methods Three EA cohorts (Reade, Etude et Suivi des Polyarthrites Indifférenciées Récentes (ESPOIR) and Early Arthritis Clinic (EAC)) were analysed. Clinical data were collected up to 24 years. Hands and feet radiographs were scored according to the Sharp van der Heijde (SvdH) method. Latent class analysis was applied to determine the EA phenotypes at baseline. Each class received a label reflecting its most prominent features. Prognostic outcomes included Health Assessment Questionnaire (HAQ), Short Form 36 (SF36) and SvdH score. The association between class membership and outcomes over time was tested in multivariable models.Results In total, 390 (Reade), 798 (ESPOIR) and 3991 (EAC) patients were analysed separately. Two classes with symmetrical polyarthritis emerged; one of these labelled as autoimmune inflammatory polyarthritis (AIPA), had high likelihood of acute phase reactants (APR) elevation and autoantibody positivity, while the other (mild-inflammatory polyarthritis; MIPA) had not. A third class had oligoarthritis of upper limbs (OAUL) and could be subdivided into autoimmune OAUL and mild-inflammatory OAUL. A fifth class had oligoarthritis of lower limbs. The SvdH scores were worse in patients with APR/autoantibodies (AIPA) than in those without (MIPA). No clinically meaningful differences across classes in HAQ or SF36 over time were found.Conclusion Radiographic progression over time primarily occurs in EA patients with APR/autoantibodies. The absence of these markers, however, does not necessarily translate into better long-term function and quality of life. Clinicians should not only aim at preventing joint damage, but look beyond structural progression in order to further improve the lives of people with EA.

Abstract Background Rheumatic and Musculoskeletal Diseases (RMDs) substantially impact the lives of patients, with complex associations between disease severity and self-perceived health status. In this regard, the Coping with Rheumatic Stressors (CORS) questionnaire was developed to measure how patients with RMDs cope with stressors such as pain, limitations or dependency. The CORS is not currently available in Spanish, and therefore the adaptation of this instrument is needed. Objective First, to cross-culturally adapt the CORS into Spanish for Spain. Secondly, to test the conceptual equivalence of the translated version in patients with axial spondyloarthritis (axSpA). Methods A translation of the CORS into Spanish was performed adhering to the forward-backward procedure described by Beaton. Two translators produced independent forward translations of the item content, response options, and instructions of the CORS into Spanish. Both versions were harmonized in a consensual version. Another translator back-translated the synthesized version into Dutch. A scientific committee including all the translators, one methodologist and a rheumatologist, held a meeting and reached consensus on discrepancies to develop a final draft version of the Spanish CORS. Then, a field test with cognitive debriefing was conducted, involving a sample of 10 patients with axSpA. Results The translation process of the CORS was completed after the discussion of some discrepancies throughout the process. The first translation was done without major complications. Back-translation presented some discrepancies. These led to minor modifications in the wording in one response option and 15 questionnaire items. The scientific committee agreed upon a final version of the questionnaire. Cognitive debriefing, led to minor modifications; for example, three respondents indicated that one of the statements in the instructions was syntactically complex (“indique cuán a menudo usted ha llevado a cabo dicho comportamiento”) which led to its adjustment. The process indicated that the final CORS Spanish questionnaire was clear and understandable to all patients. Conclusions The Spanish version of the CORS showed good cross-cultural validity and good face validity according to the field test. Before the Spanish CORS is implemented, further validation is in progress to test the psychometric properties of the instrument in patients with axSpA.

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.

Objectives To update the evidence on imaging for diagnosis, monitoring and outcome prediction in large vessel vasculitis (LVV) to inform the 2023 update of the European Alliance of Associations for Rheumatology recommendations on imaging in LVV.Methods Systematic literature review (SLR) (2017–2022) including prospective cohort and cross-sectional studies (>20 participants) on diagnostic, monitoring, outcome prediction and technical aspects of LVV imaging. Diagnostic accuracy data were meta-analysed in combination with data from an earlier (2017) SLR.Results The update retrieved 38 studies, giving a total of 81 studies when combined with the 2017 SLR. For giant cell arteritis (GCA), and taking clinical diagnosis as a reference standard, low risk of bias (RoB) studies yielded pooled sensitivities and specificities (95% CI) of 88% (82% to 92%) and 96% (95% CI 86% to 99%) for ultrasound (n=8 studies), 81% (95% CI 71% to 89%) and 98% (95% CI 89% to 100%) for MRI (n=3) and 76% (95% CI 67% to 83%) and 95% (95% CI 71% to 99%) for fluorodeoxyglucose positron emission tomography (FDG-PET, n=4), respectively. Compared with studies assessing cranial arteries only, low RoB studies with ultrasound assessing both cranial and extracranial arteries revealed a higher sensitivity (93% (95% CI 88% to 96%) vs 80% (95% CI 71% to 87%)) with comparable specificity (94% (95% CI 83% to 98%) vs 97% (95% CI 71% to 100%)). No new studies on diagnostic imaging for Takayasu arteritis (TAK) were found. Some monitoring studies in GCA or TAK reported associations of imaging with clinical signs of inflammation. No evidence was found to determine whether imaging severity might predict worse clinical outcomes.Conclusion Ultrasound, MRI and FDG-PET revealed a good performance for the diagnosis of GCA. Cranial and extracranial vascular ultrasound had a higher pooled sensitivity with similar specificity compared with limited cranial ultrasound.

Objectives To identify criteria and descriptors used to measure response to treatment and change in disease activity in giant cell arteritis (GCA).Methods A systematic literature review (SLR) to retrieve randomised controlled trials (RCTs) and longitudinal observational studies (LOS). Criteria and descriptors of active disease, remission, response, improvement, worsening and relapse were extracted. RCTs, LOS with >20 subjects, and qualitative research studies were included.Results 10 593 studies were retrieved, of which 116 were included (11 RCTs, 104 LOS, 1 qualitative study). No unified definition of response to therapy was found. Most RCTs used composite endpoints to assess treatment outcomes. Active disease was described in all RCTs and 19% of LOS; and was largely defined by a combination of clinical and laboratory components. Remission was reported in 73% of RCTs and 42% of LOS; It was predominantly defined as the combination of clinical and laboratory components. One LOS reported response with a definition resembling the definition of remission from other studies. Improvement was rarely used as an endpoint and it was mostly a surrogate of remission. No study specifically defined worsening. Relapse was reported in all RCTs and 86% of LOS. It was predominantly defined as the combination of clinical, laboratory and treatment components.Conclusions The results of this SLR demonstrate that definitions of response used in clinical studies of GCA are scant and heterogeneous. RCTs and LOS mainly used remission and relapse as treatment outcomes. The descriptors identified will inform the development of the future European Alliance of Associations for Rheumatology-American College of Rheumatology response criteria for GCA.

Abstract Objective To assess the efficacy and safety of infliximab versus placebo in the treatment of patients with juvenile-onset spondyloarthritis (JoSpA). Methods Phase III, randomized, double-blind, placebo-controlled trial of 12 weeks that included patients ≤ 18 years old with JoSpA not responding to nonsteroidal anti-inflammatory drugs, sulfasalazine, or methotrexate. Patients were randomly assigned 1:1 to the infusion of infliximab 5mg/kg or placebo; completers entered then an open-label extension (OLE) period of 42 weeks. The primary endpoint was the number of active joints. Secondary outcomes included the assessment of disease activity, tender entheses, spinal mobility, serum C-reactive protein (CRP), the Bath Ankylosing Spondylitis Disease Activity and Functional Index, and the Childhood Health Assessment Questionnaire (CHAQ). Results We randomized 12 patients to infliximab and 14 to placebo. No significant differences were found between groups at baseline. At week 12, the mean number of active joints was 1.4 (SD 2.4) in the infliximab group and 4.1 (SD 3.0) in the placebo group (p = 0.0002). A repeated-measures mixed model analysis that included all endpoints in the study demonstrated sustained favourable outcomes of infliximab for active joints, tender joints, swollen joints, and tender enthesis counts, as well as for CHAQ and CRP (p < 0.01). Adverse events were more frequent in the infliximab group, including infections and infusion reactions, but none of them was serious. Conclusion Infliximab is efficacious for patients with JoSpA with an inadequate response to conventional treatment. No serious adverse events with the use of infliximab were observed.

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 (rs0.46–0.73), and with higher correlation coefficients than mSASSS (rs0.34–0.64), 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.

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.

BackgroundThe use of social media in health care may serve as a beneficial tool for education, information dissemination, telemedicine, research, networking, and communications. To better leverage the benefits of social media, it is imperative to understand the patterns of its use and potential barriers to its implementation in health care. A previous study in 2016 that investigated social media use among young clinical rheumatologists (≤45 years) and basic scientists showed that there was substantial social media use among them for social and professional reasons. However, there is a limited inquiry into social media use in different areas of rheumatology, such as spondyloarthritis. ObjectiveWe aimed to explore the motivations, barriers, and patterns of social media use among an international group of experts in spondyloarthritis. MethodsWe distributed a web-based survey via email from March 2021 to June 2021 to 198 members of the Assessment of Spondyloarthritis International Society. It contained 24 questions about demographic characteristics, patterns of current social media use, and perceptions of utility. Univariable and multivariable logistic regression analyses were performed to identify the characteristics associated with use trends. ResultsThe response rate was 78.8% (156/198). Of these, 93.6% (146/156) of participants used at least one social media platform. Apart from internet-based shopping and entertainment, the use of social media for clinical updates (odds ratio [OR] 6.25, 95% CI 2.43-16.03) and research updates (OR 3.45, 95% CI 1.35-8.78) were associated with higher social media consumption. Among the respondents, 66% (103/156) used social media in a work-related manner. The use of social media for new web-based resources (OR 6.55, 95% CI 2.01-21.37), interaction with international colleagues (OR 4.66, 95% CI 1.21-17.90), and establishing a web-based presence (OR 4.05, 95% CI 1.25-13.13) were associated with higher levels of consumption for work-related purposes. Time investment, confidentiality concerns, and security concerns were the top 3 challenges to a wider adoption of social media. ConclusionsMost respondents (103/156, 66%) use social media in a work-related manner. Professional development, establishing a web-based presence, and international collaboration were associated with higher use. Challenges to social media adoption should be addressed to maximize its benefits.

Objectives To investigate the influence of gender on disease outcomes in patients with spondyloarthritis (SpA), including across SpA subtypes.Methods Data from 4185 patients of 23 countries with a diagnosis of axial SpA (axSpA), peripheral SpA (pSpA) or psoriatic arthritis (PsA) from the Assessment of SpondyloArthritis International Society (ASAS)-perSpA study were analysed. Associations between gender and disease activity (Ankylosing Spondylitis Disease Activity Score (ASDAS), Bath Ankylosing Spondylitis Disease Activity Score (BASDAI), C-reactive protein (CRP)), function (Bath Ankylosing Spondylitis Functional Index (BASFI)) and overall health (ASAS Health Index (ASAS HI), European Quality of Life Five Dimension (EQ-5D)) outcomes were investigated. Multilevel multivariable linear mixed models adjusted for relevant confounders (and stratified by disease subtype in case of a relevant interaction) were used.Results In total, 65%, 10% and 25% of patients had axSpA, pSpA and PsA, respectively. axSpA was more frequent in males (68%), whereas pSpA and PsA were more frequent in females (53% and 52%, respectively). A significant interaction between gender and disease subtype was found for ASDAS, BASDAI and BASFI. While being female independently contributed to higher BASDAI across the three disease subtypes (with varying magnitude), female gender was only associated with higher ASDAS in pSpA (β (95% CI): 0.36 (0.15 to 0.58)) and PsA (0.25 (0.12 to 0.38)) but not in axSpA (0.016 (−0.07 to 0.11)). No associations were observed between gender and CRP levels. Female gender was associated with higher ASAS HI and EQ-5D, without differences across disease subtype.Conclusion Female gender is associated with less favourable outcome measures across the SpA spectrum. However, while female gender influences BASDAI across the three subtypes, ASDAS is associated with gender only in pSpA and PsA but not in axSpA. Therefore, ASDAS is an appropriate instrument both for females and males with axSpA.

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.

Abstract Background To investigate whether the reason to discontinue the first TNF inhibitor (TNFi) affects the response to the second TNFi in axial spondyloarthritis (axSpA). Methods Patients with axSpA from the Rheumatic Diseases Portuguese Register (ReumaPt), who discontinued their first TNFi and started the second TNFi between June 2008 and May 2018, were included. Response was assessed by the Ankylosing Spondylitis Disease Activity Score (ASDAS) clinically important improvement (ASDAS-CII), major important improvement (ASDAS-MI), low disease activity (ASDAS-LDA), and inactive disease (ASDAS-ID). The reason for discontinuation of the first TNFi was defined, according to ASDAS-CII as primary failure (no response ≤ 6 months), secondary failure (response ≤ 6 months but lost thereafter), adverse events, and others. The association between the reason for discontinuation of the first TNFi and response to the second TNFi over time was assessed in multivariable generalized equation (GEE) models. Results In total, 193 patients were included. The reason for discontinuation of the first TNFi did not influence the response to the second TNFi, according to the ASDAS-CII. However, a difference was found with more stringent outcomes, e.g., there was a higher likelihood to achieve ASDAS-ID with the second TNFi for patients discontinuing the first TNFi due to secondary failure (OR 7.3 [95%CI 1.9; 27.7]), adverse events (OR 9.1 [2.5; 33.3]), or other reasons (OR 7.7 [1.6; 37.9]) compared to primary failure. Conclusion Patients with axSpA with secondary failure to their first TNFi, compared to those with primary failure, have a better response to the second TNFi according to stringent outcomes.

Axial spondyloarthritis (axSpA) is a chronic rheumatic disease characterised by inflammation predominantly involving the spine and the sacroiliac joints. In some patients, axial inflammation leads to irreversible structural damage that in the spine is usually quantified by the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). Available therapeutic options include biological disease-modifying antirheumatic drugs (bDMARDs), which have been proven effective in suppressing inflammation in several randomised controlled trials (RCT), the gold standard for evaluating causal treatment effects. RCTs are, however, unfeasible for testing structural effects in axSpA mainly due to the low sensitivity to change of the mSASSS. The available literature therefore mainly includes observational research, which poses serious challenges to the determination of causality. Here, we review the studies testing the effect of bDMARDs on spinal radiographic progression, making use of the principles of causal inference. By exploring the assumptions of causality under counterfactual reasoning (exchangeability, positivity and consistency), we distinguish between studies that likely have reported confounded treatment effects and studies that, on the basis of their design, have more likely reported causal treatment effects. We conclude that bDMARDs might, indirectly, interfere with spinal radiographic progression in axSpA by their effect on inflammation. Innovations in imaging are expected, so that placebo-controlled trials can in the future become a reality. In the meantime, causal inference analysis using observational data may contribute to a better understanding of whether disease modification is possible in axSpA.

Abstract Background Rheumatoid arthritis (RA) is characterized by the presence of autoantibodies like rheumatoid factor (RF), anti-cyclic citrullinated peptide-2 (anti-CCP2), and anti-carbamylated protein (anti-CarP) antibodies. It is currently unclear whether changes in autoantibody levels are associated with disease activity/treatment outcomes and whether they are modified by treatment intensity. Therefore, we determined longitudinal changes in RA-autoantibody levels, the association between these changes and activity score (DAS) and treatment outcomes, and the effect of intensity of immunosuppressive treatment on levels. Methods In 381 seropositive RA patients from the IMPROVED study, we measured IgG, IgM, and IgA of anti-CCP2 and anti-CarP; IgM and IgA of RF; and IgG against four citrullinated and two acetylated peptides at 4-month intervals over the first year of treatment. Following initial prednisone and methotrexate (MTX), treatment was changed every 4 months aiming for DAS

Objective To summarise the methodological aspects in studies with work participation (WP) as outcome domain in inflammatory arthritis (IA) and other chronic diseases.Methods Two systematic literature reviews (SLRs) were conducted in key electronic databases (2014–2019): search 1 focused on longitudinal prospective studies in IA and search 2 on SLRs in other chronic diseases. Two reviewers independently identified eligible studies and extracted data covering pre-defined methodological areas.Results In total, 58 studies in IA (22 randomised controlled trials, 36 longitudinal observational studies) and 24 SLRs in other chronic diseases were included. WP was the primary outcome in 26/58 (45%) studies. The methodological aspects least accounted for in IA studies were as follows (proportions of studies positively adhering to the topic are shown): aligning the studied population (16/58 (28%)) and sample size calculation (8/58 (14%)) with the work-related study objective; attribution of WP to overall health (28/58 (48%)); accounting for skewness of presenteeism/sick leave (10/52 (19%)); accounting for work-related contextual factors (25/58 (43%)); reporting attrition and its reasons (1/58 (2%)); reporting both aggregated results and proportions of individuals reaching predefined meaningful change or state (11/58 (16%)). SLRs in other chronic diseases confirmed heterogeneity and methodological flaws identified in IA studies without identifying new issues.Conclusion High methodological heterogeneity was observed in studies with WP as outcome domain. Consensus around various methodological aspects specific to WP studies is needed to improve quality of future studies. This review informs the EULAR Points to Consider for conducting and reporting studies with WP as an outcome in IA.

Introduction Although patient-reported outcome measures (PROMs) are increasingly used in clinical practice and research, it is unclear whether these instruments cover the perspective of young people with inflammatory arthritis (IA). The aims of this study were to explore whether PROMs commonly used in IA adequately cover the perspective of young people from different European countries.Methods A multinational qualitative study was conducted in Austria, Croatia, Italy and the Netherlands. Young people with either rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), Still’s disease, psoriatic arthritis (PsA) or spondyloarthritis (SpA), aged 18–35 years, participated in semistructured focus group interviews. Thematic analysis was used and data saturation was defined as no new emergent concepts in at least three subsequent focus groups.Results Fifty-three patients (21 with RA/JIA/Still’s, 17 with PsA, 15 with SpA; 72% women) participated in 12 focus groups. Participants expressed a general positive attitude towards PROMs and emphasised their importance in clinical practice. In addition, 48 lower level concepts were extracted and summarised into 6 higher level concepts describing potential issues for improvement. These included: need for lay-term information regarding the purpose of using PROMs; updates of certain outdated items and using digital technology for data acquisition. Some participants admitted their tendency to rate pain, fatigue or disease activity differently from what they actually felt for various reasons.Conclusions Despite their general positive attitude, young people with IA suggested areas for PROM development to ensure that important concepts are included, making PROMs relevant over the entire course of a chronic disease.

Background The CHIC study (COVID-19 High-intensity Immunosuppression in Cytokine storm syndrome) is a quasi-experimental treatment study exploring immunosuppressive treatment versus supportive treatment only in patients with COVID-19 with life-threatening hyperinflammation. Causal inference provides a means of investigating causality in non-randomised experiments. Here we report 14-day improvement as well as 30-day and 90-day mortality.Patients and methods The first 86 patients (period 1) received optimal supportive care only; the second 86 patients (period 2) received methylprednisolone and (if necessary) tocilizumab, in addition to optimal supportive care. The main outcomes were 14-day clinical improvement and 30-day and 90-day survival. An 80% decline in C reactive protein (CRP) was recorded on or before day 13 (CRP >100 mg/L was an inclusion criterion). Non-linear mediation analysis was performed to decompose CRP-mediated effects of immunosuppression (defined as natural indirect effects) and non-CRP-mediated effects attributable to natural prognostic differences between periods (defined as natural direct effects).Results The natural direct (non-CRP-mediated) effects for period 2 versus period 1 showed an OR of 1.38 (38% better) for 14-day improvement and an OR of 1.16 (16% better) for 30-day and 90-day survival. The natural indirect (CRP-mediated) effects for period 2 showed an OR of 2.27 (127% better) for 14-day improvement, an OR of 1.60 (60% better) for 30-day survival and an OR of 1.49 (49% better) for 90-day survival. The number needed to treat was 5 for 14-day improvement, 9 for survival on day 30, and 10 for survival on day 90.Conclusion Causal inference with non-linear mediation analysis further substantiates the claim that a brief but intensive treatment with immunosuppressants in patients with COVID-19 and systemic hyperinflammation adds to rapid recovery and saves lives. Causal inference is an alternative to conventional trial analysis, when randomised controlled trials are considered unethical, unfeasible or impracticable.

Background Multidisciplinary collaboration is defined as a collective work involving multiple disciplines and is common in clinical care and research. Our aim was to describe current clinical and research collaboration among young specialists and to identify unmet needs in this area.Methods An online survey was disseminated by email and social media to members of the EMerging EUlar NETwork, the Young Nephrologists’ Platform, the Paediatric Rheumatology European Society Emerging Rheumatologists and Researchers and the European Academy of Allergy and Clinical Immunology Junior Members.Results Of 303 respondents from 36 countries, 61% were female, 21% were aged below 30 years and 67% were aged 31–40 years. Young rheumatologists were the most represented (39%), followed by young nephrologists (24%), young paediatricians (20%), young allergologists (11%) then young internists (3%) and 3% other specialities. Collaborations were reported frequently by phone and email, also by various combined clinics while common local multidisciplinary meetings were uncommon. 96% would like to develop clinical research collaborations and 69% basic research collaborations. The majority of young specialists would be interested in online (84%) and/or 1–2 days (85%) common courses including case discussion (81%) and training workshops (85%), as well as webinars recorded with several specialists on a specific disease (96%).Conclusions This collaborative initiative highlighted wishes from young specialists for developing (1) regular local multidisciplinary meetings to discuss complex patients, (2) clinical research collaboration with combined grants and (3) multidisciplinary online projects such as common courses, webinars and apps.

Objectives To gain insight into current methods and practices for the assessment of competences during rheumatology training, and to explore the underlying priorities and rationales for competence assessment.Methods We used a qualitative approach through online focus groups (FGs) of rheumatology trainers and trainees, separately. The study included five countries—Denmark, the Netherlands, Slovenia, Spain and the United Kingdom. A summary of current practices of assessment of competences was developed, modified and validated by the FGs based on an independent response to a questionnaire. A prioritising method (9 Diamond technique) was then used to identify and justify key assessment priorities.Results Overall, 26 participants (12 trainers, 14 trainees) participated in nine online FGs (2 per country, Slovenia 1 joint), totalling 12 hours of online discussion. Strong nationally (the Netherlands, UK) or institutionally (Spain, Slovenia, Denmark) standardised approaches were described. Most groups identified providing frequent formative feedback to trainees for developmental purposes as the highest priority. Most discussions identified a need for improvement, particularly in developing streamlined approaches to portfolios that remain close to clinical practice, protecting time for quality observation and feedback, and adopting systematic approaches to incorporating teamwork and professionalism into assessment systems.Conclusion This paper presents a clearer picture of the current practice on the assessment of competences in rheumatology in five European countries and the underlying rationale of trainers’ and trainees’ priorities. This work will inform EULAR Points-to-Consider for the assessment of competences in rheumatology training across Europe.

Objective To summarise the literature on the assessment of competences in postgraduate medical training.Methods A systematic literature review was performed within a EULAR taskforce on the assessment of competences in rheumatology training and other related specialities (July 2019). Two searches were performed: one search for rheumatology and one for related medical specialities. Two reviewers independently identified eligible studies and extracted data on assessment methods. Risk of bias was assessed using the medical education research study quality instrument.Results Of 7335 articles in rheumatology and 2324 reviews in other specialities, 5 and 31 original studies were included, respectively. Studies in rheumatology were at variable risk of bias and explored only direct observation of practical skills (DOPS) and objective structured clinical examinations (OSCEs). OSCEs, including clinical, laboratory and imaging stations, performed best, with a good to very good internal consistency (Cronbach’s α=0.83–0.92), and intrarater reliability (r=0.80–0.95). OSCEs moderately correlated with other assessment tools: r=0.48 vs rating by programme directors; r=0.2–0.44 vs multiple-choice questionnaires; r=0.48 vs DOPS. In other specialities, OSCEs on clinical skills had a good to very good inter-rater reliability and OSCEs on communication skills demonstrated a good to very good internal consistency. Multisource feedback and the mini-clinical evaluation exercise showed good feasibility and internal consistency (reliability), but other data on validity and reliability were conflicting.Conclusion Despite consistent data on competence assessment in other specialities, evidence in rheumatology is scarce and conflicting. Overall, OSCEs seem an appropriate tool to assess the competence of clinical skills and correlate well with other assessment strategies. DOPS, multisource feedback and the mini-clinical evaluation exercise are feasible alternatives.

Younger patients with COVID-19 may experience an exaggerated immune response to SARS-CoV-2 infection and develop cytokine release syndrome (CRS), which may be life threatening. There is no proven antiviral therapy for COVID-19 so far, but profound immunosuppression has recently been suggested as a treatment for COVID-19-associated CRS. We present a case of life-threatening CRS caused by COVID-19 infection with a favourable response to immunosuppressive therapy with tocilizumab (TCZ). The rapid clinical and biochemical improvement following TCZ administration suggests that treatment with immunotherapy can be life-saving in selected patients with COVID-19-induced CRS.

Objective This study aims to (1) assess the perceived need for a postdoctoral (post-doc) mentoring programme in rheumatology, (2) describe the characteristics and organisational aspects of a pilot mentoring programme implemented by the EMerging European League Against Rheumatism NETwork (EMEUNET) and (3) report mentors’ and mentees’ evaluation of the pilot programme.Methods An online survey was conducted among young researchers in rheumatology to evaluate the need and preferred characteristics of a post-doc mentoring initiative. Informed by the survey, a pilot programme was designed and launched. The pilot programme was evaluated with 3-month, 6-moth and 12-month surveys and interviews with mentees and a 12-month survey among mentors, after completion.Results From 275 responses (43 countries, 86% from Europe) collected, analyses were restricted to the target population (total population=158; post-docs (n=103 (65%)) and PhD students (n=55 (35%))). There was a clear need (99% positive responses) for a post-doc mentoring programme. Discussions about current and new projects, and how to lead projects were ranked as priorities in post-doc mentoring. The most desired mentor attribute was generosity and interest in helping (86%), followed by research experience (68%) and having a well-established network (66%). The pilot programme included four mentees (through competitive application) allocated to three mentors. Evaluation surveys and interviews revealed that the programme organisation and content were well appreciated by mentees and mentors.Conclusions The EMEUNET post-doc mentoring programme addresses unmet need for mentoring, is viable and appreciated by mentors and mentees. The programme structure and content are transferable to other fields where there is need for academic career mentoring.

Objective To study changes on MRI of the spine and sacroiliac joint (SIJ) in early axial spondyloarthritis (axSpA) over time.Methods In the Devenir des Spondyloarthropathies Indifférenciées Récentes cohort, MRI-spine and MRI-SIJ at baseline and 2 and 5 years were scored by central readers for bone marrow oedema (BME), fatty lesions, erosions, sclerosis, ankylosis and spinal bone spurs. The average mean number of lesions was reported or the agreement of ≥2 out of 3 readers for binary outcomes. Net progression was calculated by subtracting the patients that ‘improved’ from those that ‘worsened’ divided by the total number of patients.Results Over 5 years, in 155 patients with axSpA (mean age 33.5 (SD 8.9) years, symptom duration 1.4 (0.8) years, 63% human leucocyte antigen+, 14% modified New York+), BME on MRI-SIJ decreased by a mean Spondyloarthritis Research Consortium of Canada score of 1.4 (SD 6.5) (p=0.009). The largest BME decrease was observed in patients using biological disease-modifying antirheumatic drugs at 5 years. Spinal BME increased by 0.3 (4.6) (p=0.41). Fatty lesions and/or erosions on MRI-SIJ increased by a mean of 1.0 (SD 2.6) (p

Objectives To compare definitions of high disease activity of the Ankylosing Spondylitis Disease Activity Score (ASDAS) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) in selecting patients for treatment with biologic disease-modifying antirheumatic drugs (bDMARDs).Methods Patients from Rheumatic Diseases Portuguese Register (Reuma.pt) with a clinical diagnosis of axial spondyloarthritis (axSpA) were included. Four subgroups (cross-tabulation between ASDAS (≥2.1) and BASDAI (≥4) definitions of high disease activity) were compared regarding baseline characteristics and response to bDMARDs at 3 and 6 months estimated in multivariable regression models.Results Of the 594 patients included, the majority (82%) had both BASDAI≥4 and ASDAS ≥2.1. The frequency of ASDAS ≥2.1, if BASDAI

Abstract Background Although gender differences have been observed in the severity of axial spondyloarthritis (axSpA), gender differences in disease presentation of early axSpA have not been thoroughly investigated. In particular, their impact on the diagnostic process is unknown. Methods Baseline data from the SPondyloArthritis Caught Early cohort, which includes patients with chronic back pain (CBP; duration ≥ 3 months and ≤ 2 years, age of onset

Abstract Background We aimed to explore whether country of residence or specific country characteristics are associated with work outcomes in rheumatoid arthritis (RA). Methods Data from the 17 countries participating in the Comorbidities in RA (COMORA) study were used. Work outcomes were measured by the Work Productivity and Activity Impairment Questionnaire, addressing employment (yes/no), absenteeism (percentage of time; 3 categories) and presenteeism (percentage of at-work productivity restrictions; 4 categories). Contribution of country of residence, gross domestic product (GDP), Human Development Index (HDI), unemployment rate, social protection expenditures (SPE) or world region to work outcomes was investigated in adjusted (ordered) logistic regressions. Results The patients (n = 2395) were younger than 60 years; mean age 48 (SD 9.2) years, 1972 (84%) female and 1065 (45%) employed. Large country differences were found. Taking the country with the best work outcome as reference, Moroccan patients had the lowest odds of being employed (OR 0.2 (95% CI 0.1; 0.3) vs. Germany) and highest odds of absenteeism (OR 13.2 (3.6; 48.3) vs. Japan). Patients in Taiwan had the highest odds of presenteeism (OR 13.0 (5.5; 30.9) vs. Venezuela). All country indices except SPE were associated with work outcomes. For example, patients in low-GDP countries had lower odds of employment (OR 0.6 (0.5; 0.8)), higher odds of absenteeism (OR 2.8 (2.0; 4.1)), but lower odds of presenteeism (OR 0.5 (0.4; 0.7)) compared to higher-GDP countries. Conclusion Substantial differences in work outcomes among patients with RA were observed between countries. Lower economic wealth and human development of countries were associated with worse employment and higher absenteeism, but lower presenteeism.

Real-world data are increasingly available to investigate ‘real-world’ safety and efficacy. However, since treatment in observational studies is not randomly allocated, confounding by indication may occur, in which differences in patient characteristics may influence both treatment choices and treatment responses. A popular method to adjust for this type of bias is the use of propensity scores (PS). The PS is a score between 0 and 1 that reflects the likelihood per patient of receiving one of the treatment categories of interest conditional on a set of variables. At least in theory, in patients with similar PS, the treatment prescribed will be independent of these variables (pseudorandomisation). But researchers using PS sometimes fail to recognise important methodological flaws which can lead to spurious conclusions. These include perfect prediction of treatment allocation, untied observations and lack of generalisability due to oversimplification of complex clinical scenarios. In this viewpoint we will discuss the most commonly encountered flaws and provide a stepwise description on the estimation and use of PS, such that in future publications these flaws can be avoided.

Stopping or preventing structural progression is a goal common to all inflammatory rheumatic diseases. Imaging may capture structural progression across diseases, but is susceptible to measurement error. Progression can be analysed as a continuous change score over time (eg, mean change of the van der Heijde-modified Sharp score) or as a binary change score (eg, percentage of progressors according to the modified New York criteria). Here, we argue that the former takes measurement error into account while the latter ignores it, which may lead to spurious conclusions. We will argue that assumptions underlying commonly used binary definitions of progression are false and we propose a method that incorporates (inevitable) measurement error.