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.

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).

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.

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.

Efficacy of a tight-control and treat-to-target strategy in axial spondyloarthritis: results of the open-label, pragmatic, cluster-randomised TICOSPA trial.

OBJECTIVES: To compare the benefits of a tight-control/treat-to-target strategy (TC/T2T) in axial spondyloarthritis (axSpA) with those of usual care (UC). METHODS: Pragmatic, prospective, cluster-randomised, controlled, open, 1-year trial (NCT03043846). 18 centres were randomised (1:1). Patients met Axial Spondylo Arthritis International Society (ASAS) criteria for axSpA, had an Ankylosing Spondylitis Disease Activity Score (ASDAS) ≥2.1, received non-optimal treatment by non-steroidal anti-inflammatory drugs and were biologic-naive. INTERVENTIONS: (1) TC/T2T: visits every 4 weeks and prespecified strategy based on treatment intensification until achieving target (ie, ASDAS <2.1); (2) UC: visits every 12 weeks and treatment at the rheumatologist's discretion. MAIN OUTCOME: Percentage of patients with a ≥30% improvement on the ASAS-Health Index (ASAS-HI). Other efficacy outcomes and adverse events were recorded. A health economic evaluation was performed. STATISTICAL ANALYSIS: Two-level mixed models were used to estimate efficacy outcomes. Cost-effectiveness was assessed by the incremental cost per quality-adjusted life-year (QALY) gained for TC/T2T versus UC. RESULTS: 160 patients were included (80/group). Mean (SD) age was 37.9 (11.0) years and disease duration was 3.7 (6.2) years; 51.2% were men. ASDAS at inclusion was 3.0 (0.7), and ASAS-HI was 8.6 (3.7). ASAS-HI improved by ≥30% in 47.3% of the TC/T2T arm and in 36.1% of those receiving UC (non-significant). All secondary efficacy outcomes were more frequent in the TC/T2T arm, although not all statistically significant. Safety was similar in both arms. From a societal perspective, TC/T2T resulted in an additional 0.04 QALY, and saved €472 compared with UC. CONCLUSION: TC/T2T was not significantly superior to UC for the primary outcome, while many secondary efficacy outcomes favoured it, had a similar safety profile and was favourable from a societal health economic perspective. TRIAL REGISTRATION NUMBER: NCT03043846.

Determinants of the patient global assessment of well-being in early axial spondyloarthritis: 5-year longitudinal data from the DESIR cohort.

OBJECTIVES: To investigate the determinants of patient well-being over time, and the influence of age, gender and education in patients with early axial spondyloarthritis (axSpA). METHODS: Five-year data from DESIR, a cohort of early axSpA, were analysed. The outcome was the BAS-G over 5 years. Generalized estimating equations (GEE) were used to test the relationship between potential explanatory variables from five outcome domains (disease activity, physical function, spinal mobility, structural damage and axial inflammation) and BAS-G over time. Longitudinal relationships were analysed using an autoregressive GEE model. Age, gender and educational level were tested as effect modifiers or confounders. RESULTS: A total of 708 patients were included. Higher BASDAI questions on fatigue [ß (95% CI): 0.17 (0.13, 0.22)], back pain [0.51 (0.46, 0.56)], peripheral joint pain [0.08 (0.04, 0.12)] and severity of morning stiffness [0.08 (0.03-0.13)], and higher BASFI [0.14 (0.08, 0.19)] were associated with a higher BAS-G. In the autoregressive model, the same variables except for morning stiffness were associated with a worsening in BAS-G. Age, gender and educational level were neither effect modifiers nor confounders. CONCLUSION: A higher level of back pain is associated with a worsening of patient well-being, as are, though to a lesser extent, higher levels of fatigue, peripheral joint pain and physical disability. Age, gender and educational level do not have an impact on these relationships.

Routine alcohol screening in the ED: unscreened patients have an increased risk for hazardous alcohol use.

BACKGROUND: Routine screening programmes for hazardous alcohol use in the ED miss large numbers of patients. We investigated whether patient-related or staff-related factors cause screening failures and whether unscreened patients are at increased risk of hazardous alcohol use. METHODS: This is a secondary analysis of a prospective study. From November 2012 to November 2013, all adult patients visiting a Dutch inner city ED were screened for hazardous alcohol consumption using the Alcohol Use Disorders Identification Test-Consumption. Reasons for failure of screening were categorised as: (A) patient is unable to cooperate (due to illness or pain, decreased consciousness or incomprehension due to intoxication, psychiatric, cognitive or neurological disorder or language barrier), (B) healthcare professional forgot to ask, (C) patient refuses cooperation and (D) screening was recently performed (<6 months ago). Presence of risk factors for hazardous alcohol use was compared between screened and unscreened patients. RESULTS: Of the 28 019 ED patients, 18 310 (65%) were screened and 9709 (35%) were not. In 7150 patients staff forgot to screen, whereas 2559 patients were not screened due to patient factors (2340 being unable and 219 unwilling). Patients with any of these risk factors were less likely to be screened: male sex, alcohol-related visit, any intoxication, head injury, any kind of wound and major trauma. In multivariate analysis, all these risk factors were independently associated with not being screened. Patients with at least one risk factor for hazardous alcohol use were less likely to be screened. Highest prevalence of risk factors was found in patients unable or unwilling to cooperate. CONCLUSION: Patients who do not undergo routine screening for alcohol use at triage in the ED have an increased risk for hazardous alcohol use. These data highlight the importance of screening patients, especially those initially unwilling or unable to cooperate, at a later stage.

Correction: HLA-C*07 in axial spondyloarthritis: data from the German Spondyloarthritis Inception Cohort and the Spondyloarthritis Caught Early cohort.

The original version of this Article contained an error in the spelling of the author Denis Poddubnyy, which was incorrectly given as Denis Podubbnyy. This has now been corrected in both the PDF and HTML versions of the Article.

HLA-C*07 in axial spondyloarthritis: data from the German Spondyloarthritis Inception Cohort and the Spondyloarthritis Caught Early cohort.

We aimed to assess the mRNA expression of MHC class 1-related molecules in ankylosing spondylitis (AS) patients vs healthy controls (HCs) and, subsequently, if the absence of HLA-C*07 is associated with genetic susceptibility to axial spondyloarthritis (axSpA). HLA-C*07 was assessed in (a) an exploratory cohort of 24 AS patients vs 40 HCs, (b) a confirmatory cohort of 113 AS patients and 83 non-radiographic axSpA patients from the GErman SPondyloarthritis Inception Cohort (GESPIC) vs 134,528 German potential stem cell donors, and (c) an early back pain cohort with 94 early axSpA patients vs 216 chronic back pain (CBP) patients from the SPondyloArthritis Caught Early (SPACE) cohort. In the exploratory cohort, 79% of the AS patients were HLA-C*07 negative compared to 35% of the HCs (p < 0.001). This difference was confirmed in GESPIC with 73% of AS patients being HLA-C*07 negative compared to 50% of the controls (p < 0.0001); 59% of the nr-axSpA patients were HLA-C*07 negative. In the SPACE cohort, 70% of the axSpA patients were HLA-C*07 negative compared to 44% of CBP patients (p < 0.0001); the association between HLA-C*07 negativity and a diagnosis of axSpA was independent from HLA-B*27. In conclusion, the absence of HLA-C*07 is associated with genetic susceptibility to axSpA.

Do patients with axial spondyloarthritis with radiographic sacroiliitis fulfil both the modified New York criteria and the ASAS axial spondyloarthritis criteria? Results from eight cohorts.

BACKGROUND: Patients with spondyloarthritis with radiographic sacroiliitis are traditionally classified according to the modified New York (mNY) criteria as ankylosing spondylitis (AS) and more recently according to the Assessment of SpondyloArthritis international Society (ASAS) criteria as radiographic axial spondyloarthritis (r-axSpA). OBJECTIVE: To investigate the agreement between the mNY criteria for AS and the ASAS criteria for r-axSpA and reasons for disagreement. METHODS: Patients with back pain ≥3 months diagnosed as axSpA with radiographic sacroiliitis (mNY radiographic criterion) were selected from eight cohorts (ASAS, Esperanza, GESPIC, OASIS, Reuma.pt, SCQM, SPACE, UCSF). Subsequently, we calculated the percentage of patients who fulfilled the ASAS r-axSpA criteria within the group of patients who fulfilled the mNY criteria and vice versa in six cohorts with complete information. RESULTS: Of the 3882 patients fulfilling the mNY criteria, 93% also fulfilled the ASAS r-axSpA criteria. Inversely, of the 3434 patients fulfilling the ASAS r-axSpA criteria, 96% also fulfilled the mNY criteria. The main cause for discrepancy between the two criteria sets was the reported age at onset of back pain. CONCLUSION: Almost all patients with axSpA with radiographic sacroiliitis fulfil both ASAS and mNY criteria, which supports the interchangeable use of the terms AS and r-axSpA.

Is a positive family history of spondyloarthritis relevant for diagnosing axial spondyloarthritis once HLA-B27 status is known?

OBJECTIVES: A positive family history (PFH) of spondyloarthritis, in particular a PFH of AS or acute anterior uveitis, is associated with HLA-B27 carriership in chronic back pain patients. As it is unknown, the study aimed to investigate if a PFH contributes to diagnosing axial spondyloarthritis (axSpA) once HLA-B27 status is known. METHODS: In axSpA-suspected patients from the Assessment of SpondyloArthritis international Society (ASAS), DEvenir des Spondyloarthropathies Indifférenciéés Récentes (DESIR) and SPondyloArthritis Caught Early (SPACE) cohorts, logistic regression analyses were performed with HLA-B27 status and PFH according to the ASAS definition (ASAS-PFH) as determinants and clinical axSpA diagnosis as outcome at baseline. Analyses were repeated with a PFH of AS or acute anterior uveitis. RESULTS: In total, 1818 patients suspected of axSpA were analysed (ASAS n = 594, DESIR n = 647, and SPACE n = 577). In patients from the ASAS, DESIR and SPACE cohorts, respectively 23%, 39% and 38% had an ASAS-PFH, 52%, 58% and 43% were HLA-B27 positive, and 62%, 47% and 54% were diagnosed with axSpA. HLA-B27 was independently associated with an axSpA diagnosis in each cohort but an ASAS-PFH was not [ASAS cohort: HLA-B27 odds ratio (OR): 6.9 (95% CI: 4.7, 10.2), ASAS-PFH OR: 0.9 (95% CI: 0.6, 1.4); DESIR: HLA-B27 OR: 2.1 (95% CI: 1.5, 2.9), ASAS-PFH OR: 1.0 (95% CI 0.7, 1.3); SPACE: HLA-B27 OR: 10.4 (95% CI: 6.9, 15.7), ASAS-PFH OR: 1.0 (95% CI: 0.7, 1.5)]. Similar negative results were found for PFH of AS and acute anterior uveitis. CONCLUSION: In three independent cohorts with different ethnical backgrounds, ASAS, DESIR and SPACE, a PFH was not associated independently of HLA-B27 with a diagnosis of axSpA. This indicates that in the vast majority of patients presenting with back pain, a PFH does not contribute to the likelihood of an axSpA diagnosis if HLA-B27 status is known.

Low-dose CT detects more progression of bone formation in comparison to conventional radiography in patients with ankylosing spondylitis: results from the SIAS cohort.

OBJECTIVES: To compare the CT Syndesmophyte Score (CTSS) for low-dose CT (ldCT) with the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) for conventional radiographs (CR) in patients with ankylosing spondylitis (AS). METHODS: Patients with AS in the Sensitive Imaging in Ankylosing Spondylitis cohort had lateral cervical and lumbar spine CR and whole spine ldCT at baseline and 2 years. CR and ldCT images were scored by two readers, paired by patient, blinded to time order, per imaging modality. For the total score analysis, we used average scores of readers per corner on CR or quadrant on ldCT. For the syndesmophyte analysis we used individual reader and consensus scores, regarding new or growing syndesmophyte at the same corner/quadrant. RESULTS: 50 patients were included in the syndesmophyte analysis and 37 in the total score analysis. Mean (SD) status scores for mSASSS (range 0-72) and CTSS (range 0-552) at baseline were 17.9 (13.8) and 161.6 (126.6), and mean progression was 2.4 (3.8) and 17.9 (22.1). Three times as many patients showed new or growing syndesmophytes at ≥3 quadrants on ldCT compared with ≥3 corners on CR for individual readers; for consensus this increased to five times. In 50 patients, 36 new or growing syndesmophytes are seen on CR compared with 151 on ldCT, most being found in the thoracic spine. CONCLUSIONS: ldCT, covering the whole spine, detects more progression in the form of new and growing syndesmophytes in patients with AS compared with CR, which is limited to the cervical and lumbar spine. Most progression occurred in the thoracic spine.

Development of the CT Syndesmophyte Score (CTSS) in patients with ankylosing spondylitis: data from the SIAS cohort.

OBJECTIVES: To develop the CT Syndesmophyte Score (CTSS) for low-dose CT (ldCT) to assess structural damage in the spine of patients with ankylosing spondylitis (AS) and test its reliability. METHODS: Patientswith AS in the SIAS cohort had whole spine ldCT at baseline and 2 years. Syndesmophytes were scored in coronal and sagittal planes in eight quadrants per vertebral unit (VU) as absent=0, <50% of the intervertebral disc space (IDS)=1, ≥50%=2 or bridging the IDS=3 (range 0-552). Images were scored by two readers, paired by patient, blinded to time order. Whole spine and spinal segment status and change scores were calculated. Inter-reader reliability was assessed by intraclass correlation coefficient (ICC), smallest detectable change (SDC) and frequency of scores per VU. RESULTS: 49 patients (mean age 50 years (SD 9.8), 84% men, 88% human leucocyte antigen B27 positive) were included. Mean (SD) scores of reader 1 were: whole spine baseline status score 163 (126) and change score 16 (21), spinal segment baseline status scores 30 (41), 97 (77) and 36 (36) and change scores 2 (7), 12 (18) and 3 (4) for the cervical, thoracic and lumbar spine, respectively. Scores of reader 2 were similar. Whole spine status score ICC was 0.99 and 0.97-0.98 for spinal segments. Whole spine change score ICC was 0.77 and 0.32-0.75 for spinal segments. Whole-spine SDC was 14.4. Score distribution pattern per VU was similar between readers. CONCLUSIONS: Using the CTSS, new bone formation in the spine of patients with AS can be assessed reliably. Most progression was seen in the thoracic spine.

Imaging of the sacroiliac joints is important for diagnosing early axial spondyloarthritis but not all-decisive.

OBJECTIVES: To evaluate the contribution of the results of sacroiliac imaging to diagnosis and to the level of confidence in diagnosis in patients presenting with chronic back pain (CBP) and suspected of having axial spondyloarthritis (axSpA). METHODS: Data from 513 patients from the SPondyloArthritisCaughtEarly cohort with CBP (⩾3 months, ⩽2 years, onset <45 years) were analysed after full diagnostic work-up. Rheumatologists were asked not only to provide a diagnosis before and after the imaging results had been provided to them, but also to provide the level of confidence of this diagnosis on an 11-point numerical scale. RESULTS: Before imaging, 317/513 patients were diagnosed with axSpA. Of these patients, 178/317 (56%) did not have signs of sacroiliitis on either MRI or radiography, which led to the rheumatologist refuting the initial diagnosis of axSpA in 81/178 (46%) patients. Of the 196/513 patients without axSpA before imaging, 35/196 (18%) had signs of sacroiliitis on imaging. Subsequently, 28/35 (80%) patients were diagnosed with axSpA. Overall, imaging was incongruent with the diagnosis before imaging in 213 patients. This led to a change in diagnosis in 109/213 (51%), which corresponds to 21% (109/513) of all patients in the cohort. In general, diagnostic confidence increased by having imaging results available (from 6.2 to 7.4, P < 0.001). CONCLUSION: In patients with CBP suspected of having axSpA, sacroiliac imaging adds to the confidence in the final diagnosis. However, the number of changes in diagnosis suggests that imaging is important but not all-decisive in early axSpA diagnosis.

Impact of replacing radiographic sacroiliitis by magnetic resonance imaging structural lesions on the classification of patients with axial spondyloarthritis.

OBJECTIVES: To investigate in patients with chronic back pain of a short duration, the utility of adding structural MRI lesions of the SI joints to the imaging criterion of the Assessment of SpondyloArthritis International Society (ASAS) axial SpA (axSpA) criteria and the utility of replacement of radiographic sacroiliitis by structural MRI lesions. METHODS: MRI STIR (inflammation, MRI-SI), MRI T1-weighted images (structural lesions, MRI-SI-s) and radiographs of the SI joints of patients in the SPondyloArthritis Caught Early-cohort (chronic back pain: ⩾3 months, ⩽2 years; onset <45 years) were scored by two well-calibrated readers. Previously proposed cut-offs for a positive MRI-SI-s were used (based on <5% prevalence in no-SpA patients): erosions ⩾3, fatty lesions ⩾3, fatty lesions and/or erosions (erosions/fatty lesions) ⩾5. Using the definitions of MRI-SI-s, patients were classified according to the ASAS axSpA criteria. RESULTS: Twenty-nine of 294 patients were modified New York (mNY) positive and 32 were MRI-SI-s positive (erosions/fatty lesions ⩾5). Agreement between mNY and MRI-SI-s (erosions/fatty lesions ⩾5) was moderate (κ: 0.58). Using the erosions/fatty lesions ⩾5 cut-off, 3/294 additional patients were classified as axSpA (adding MRI). Using this cut-off instead of mNY (replacing mNY), classification did not change in 286 patients (97.3%), but 5 patients (1.7%) would not be classified as axSpA and 3 previously unclassified patients (1.0%) would be classified as axSpA. Similar results were seen for the other cut-offs (erosions ⩾3 and fatty lesions ⩾3). CONCLUSION: Assessment of structural lesions (fatty lesions and erosions) on MRI-SI instead of or in addition to conventional radiographs does not lead to a different ASAS axSpA classification in most of the patients with early disease onset. This suggests that structural lesions (fatty lesions and erosions) can be reliably used in the ASAS axSpA classification of patients, as both addition and replacement of radiographs of the SI joints.

Pathophysiology of axial spondyloarthritis: Consensus and controversies.

BACKGROUND: Axial spondyloarthritis (axSpA) is a common inflammatory arthritis of the sacroiliac joints and the spine. The best-known and most studied form of axSpA is ankylosing spondylitis. DESIGN: In this review, we provide a brief overview of the pathophysiology of axSpA. In addition, we performed a quantitative text analysis of reviews on the pathogenesis of axSpA published in the last 10 years to establish the current consensus in various fields of research into the pathogenesis of axSpA. RESULTS: There appears to be broad consensus on genetic risk factors and the involvement of the immune system in the initiation phase of the disease although little consensus was found on which specific immune cells drive disease. Moreover, despite relatively little data available, alterations in the microbiome are commonly thought to be involved in disease. Abnormal bone formation is the most prominent pathogenic factor thought to be involved in disease progression. CONCLUSION: So, although the pathophysiology of axSpA remains incompletely understood, the progress in recent years in several fields of research in axSpA including genetics, diagnosis, imaging and therapeutics, hold great promise for the future.

The yield of a positive MRI of the spine as imaging criterion in the ASAS classification criteria for axial spondyloarthritis: results from the SPACE and DESIR cohorts.

OBJECTIVES: To assess the prevalence of spinal inflammation on MRI in patients with chronic back pain (CBP) of maximally 3 years duration and to evaluate the yield of adding a positive MRI-spine as imaging criterion to the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial spondyloarthritis (axSpA). METHODS: Baseline imaging of the sacroiliac joints (X-SI), MRI of the sacroiliac joints (MRI-SI) and MRI-spine were scored by ≥2 experienced central readers per modality in the SPondyloArthritis Caught Early (SPACE) and DEvenir des Spondylarthropathies Indifférenciées Récentes (DESIR) cohorts. Inflammation suggestive of axSpA was assessed in the entire spine. A positive MRI-spine was defined by the presence of ≥5 inflammatory lesions. Alternative less strict definitions were also tested. RESULTS: In this study, 541 and 650 patients with CBP from the SPACE and DESIR cohorts were included. Sacroiliitis on X-SI and MRI-SI was found in 40/541 (7%) and 76/541 (14%) patients in SPACE, and in DESIR in 134/650 (21%) and 231/650 (36%) patients, respectively. In SPACE and DESIR, a positive MRI-spine was seen in 4/541 (1%) and 48/650 (7%) patients. Of the patients without sacroiliitis on imaging, 3/447 (1%) (SPACE) and 8/382 (2%) (DESIR) patients had a positive MRI-spine. Adding positive MRI-spine as imaging criterion led to new classification in only one patient in each cohort, as the other patients already fulfilled the clinical arm. Other definitions of a positive MRI-spine yielded similar results. CONCLUSION: In two cohorts of patients with CBP with a maximum symptom duration of 3 years, a positive MRI-spine was rare in patients without sacroiliitis on MRI-SI and X-SI. Addition of MRI-spine as imaging criterion to the ASAS axSpA criteria had a low yield of newly classified patients and is therefore not recommended.

Disease activity decrease is associated with improvement in work productivity over 1 year in early axial spondyloarthritis (SPondyloArthritis Caught Early cohort).

Objectives: To assess if a change in disease activity is associated with a change in work productivity loss (WPL) over 1 year in early axial SpA (axSpA) patients. Methods: Baseline and 1 year data of axSpA patients in the SPondyloArthritis Caught Early cohort were analysed. Linear regression models were built explaining the change in the Ankylosing Spondylitis Disease Activity Score (ASDAS) over time by the change in absenteeism, presenteeism, WPL and activity impairment over time. Effect modification and confounding were tested for age, gender, arm of Assessment of SpondyloArthritis international Society classification criteria, HLA-B27, duration of chronic back pain, profession and medication. Results: At baseline, in 105 axSpA patients (48% female, mean age 30.8 years, mean symptom duration 13.6 months, 92% HLA-B27 positive, 24% radiographic sacroiliitis), the mean ASDAS was 2.4 (s.d. 1.0), absenteeism 9% (s.d. 23), presenteeism 33% (s.d. 28), WPL 36% (s.d. 30) and activity impairment 37% (s.d. 25). After 1 year, the mean ASDAS decreased to 2.0 (s.d. 0.8) and absenteeism, presenteeism, WPL and activity impairment improved to 6% (s.d. 22), 26% (s.d. 26), 27% (s.d. 29) and 27% (s.d. 26), respectively. Models showed that if ASDAS decreased 1 unit, absenteeism, presenteeism, WPL and activity impairment improved by 5, 17, 16 and 18%, respectively. The impact of disease activity on work productivity was higher in patients with shorter symptom duration and the impact on absenteeism was higher in patients starting pharmacological treatment. Conclusions: In early axSpA patients, work productivity and daily activities are seriously impacted at baseline and 1 year. However, decreasing disease activity is associated with marked improvements in work productivity and daily activities.

IL-17-producing CD4+ T cells are increased in early, active axial spondyloarthritis including patients without imaging abnormalities.

OBJECTIVE: Increased numbers of IL-17-producing CD4(+) T cells have been observed in AS. However, it is not known whether these CD4(+) T cells are already present in early disease or if this is a late disease phenomenon only. Therefore we aimed to investigate whether IL-17-producing CD4(+) T cells are involved in early active axial SpA, including patients without imaging abnormalities, by determining the frequency and phenotype of IL-17-producing CD4(+) T cells in these patients. METHODS: Flow cytometry was used to analyse cytokine production and surface marker expression of peripheral blood mononuclear cells from 31 patients suffering from early active HLA-B27-positive axial SpA fulfilling the Assessment of SpondyloArthritis International Society criteria with or without MRI abnormalities and 21 healthy controls. RESULTS: Patients with early active axial SpA showed an increased percentage of IL-17-producing CD4(+) T cells compared with healthy controls (mean 1.1% vs 0.4%, respectively; P = 0.013). The percentage of IL-17-producing CD4(+) T cells was equally increased in patients with and without MRI abnormalities (1.2% vs 1.1%, respectively; P = 0.81). These IL-17-producing CD4(+)T cells expressed the αß T cell receptor but not the γδ T cell receptor, exhibited a memory phenotype and expressed CD161, but only sporadically expressed killer cell immunoglobulin-like receptor 3DL2 (KIR3DL2). CONCLUSION: IL-17-producing CD4(+) T cells are increased in patients with early active axial SpA both with and without MRI abnormalities. This finding shows that the frequency of IL-17-producing CD4(+) T cells is enhanced in the early stages of disease.