Window of opportunity in psoriatic arthritis: the earlier the better?

OBJECTIVES: To investigate whether there is a window of opportunity for psoriatic arthritis (PsA) patients and to assess which patient characteristics are associated with a longer diagnostic delay. METHODS: All newly diagnosed, disease-modifying antirheumatic drug-naïve PsA patients who participated in the Dutch southwest Early PsA cohoRt and had ≥3 years of follow-up were studied. First, total delay was calculated as the time period between symptom onset and PsA diagnosis made by a rheumatologist and then split into patient and physician delays. The total delay was categorised into short (<12 weeks), intermediate (12 weeks to 1 year) or long (>1 year). These groups were compared on clinical (Minimal Disease Activity (MDA) and Disease Activity index for PSoriatic Arthritis (DAPSA) remission) and patient-reported outcomes during 3 years follow-up. RESULTS: 708 PsA patients were studied of whom 136 (19%), 237 (33%) and 335 (47%) had a short, intermediate and long total delay, respectively. Patient delay was 1.0 month and physician delay was 4.5 months. Patients with a short delay were more likely to achieve MDA (OR 2.55, p=0.003) and DAPSA remission (OR 2.35,p=0.004) compared with PsA patients with a long delay. Patient-reported outcomes showed numerical but non-significant differences between the short and long delay groups. Female patients and those presenting with enthesitis, chronic back pain or normal C-reactive protein (CRP) had a longer delay. CONCLUSIONS: In PsA, referral and diagnosis within 1 year is associated with better clinical outcomes, suggesting the presence of a window of opportunity. The most gain in referral could be obtained in physician delay and in females, patients with enthesitis, chronic back pain or normal CRP.

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.

Construct validity and responsiveness of feasible composite disease activity measures for use in daily clinical practice in patients with psoriatic arthritis.

OBJECTIVE: There is a need for a widely accepted comprehensive disease activity measure for use in daily practice in patients with psoriatic arthritis (PsA). For this reason, the 3-item Visual Analogue Scale (3VAS) and 4-item Visual Analogue Scale (4VAS) were developed. This study aimed to test construct validity and responsiveness of the 3VAS and 4VAS in a population of patients with newly diagnosed PsA receiving usual care. METHODS: Components of the 3VAS (physician global, patient global, patient skin) and 4VAS (physician global, patient pain, patient joint, patient skin) were scored on 0-10 VAS scales. Agreement of low disease activity (LDA) state between 3VAS/4VAS and other composite measures was tested using Venn diagrams. Construct validity and responsiveness (3-month interval) were assessed using Spearman correlation coefficients and standardised response means (SRM) with effect sizes (ES), respectively, following hypothesis generation. Both 3VAS/4VAS were also compared with several patient-reported outcome measures. RESULTS: Data from 629 patients were used. Both 3VAS (ES=0.48, SRM 0.52) and 4VAS (ES=0.48, SRM=0.50) showed responsiveness similar to Disease Activity in PSoriatic Arthritis (DAPSA) and Disease Activity Score-28 (DAS28). Both measures had a strong correlation with DAPSA (r=0.80-0.87), Psoriatic Arthritis Disease Activity Score (PASDAS) (r=0.89) and Routine Assessment of Patient Index Data 3 (RAPID3) (r=0.84-0.92). 3VAS and 4VAS had the highest agreement with PASDAS in categorising patients to LDA at 12 months. CONCLUSION: This is the first study assessing the performance of the 3VAS and 4VAS in an observational cohort of patients with early PsA. Both measures have promising performance characteristics, showing strong correlations and good discrimination with existing composite measures. The 4VAS may be the preferred version with better face validity.

Frequency of joint inflammation is associated with local joint damage progression in rheumatoid arthritis despite long-term targeted treatment.

OBJECTIVES: To investigate whether in rheumatoid arthritis (RA) frequency of local joint inflammation is associated with radiographic joint damage progression in that joint. METHODS: Data from 473 patients with RA and available radiographs from the BeSt study were used. Patients were treated to target (Disease Activity Score of ≤2.4) for a median of 10 years. At each study visit every 3 months, joints were assessed for swelling and tenderness. Radiographs of hands and feet were made yearly. A generalised linear mixed model was used to assess the association between the percentage of study visits at which clinical inflammation was observed in a joint (cumulative inflammation) and radiographic joint damage in that same joint. Clinical inflammation was primarily defined as joint swelling (with or without joint tenderness). For secondary analyses, we also investigated joint tenderness without joint swelling. Damage was measured as the percentage of the maximum possible Sharp-Van der Heijde score in a particular joint. RESULTS: Cumulative local joint swelling was associated with local progression of radiographic damage in the same joint (ß=0.14, 95% CI 0.13 to 0.15). This association was also found in a subset of joints that were swollen at least once. Cumulative local joint tenderness without concurrent local joint swelling was less strongly associated with local radiographic joint damage progression (ß=0.04, 95% CI 0.03 to 0.05). CONCLUSIONS: In RA, long-term cumulative local joint inflammation is associated with joint damage progression in the same joint.

Impact of psoriasis remains important in psoriatic arthritis patients with low musculoskeletal disease activity.

OBJECTIVES: Achieving low disease activity (LDA) is important in patients with psoriatic arthritis. It is of value to know if health-related quality of life (HRQoL) of patients who reached musculoskeletal low disease activity can be further improved by additionally achieving remission of their psoriasis. So, the aim of this study was to assess HRQoL in patients with active psoriasis who reached disease activity in psoriatic arthritis (DAPSA) LDA after one year of follow-up. METHODS: Data were collected from the Dutch south west Psoriatic Arthritis cohort. Musculoskeletal disease activity was measured using DAPSA. Patients who reached DAPSA-LDA after one year were divided based on reaching psoriasis remission (Psoriasis Area and Severity Index [PASI] <1). HRQoL and work productivity were compared between both groups. RESULTS: After one year, 230 (44%) patients with active psoriasis at baseline reached DAPSA-LDA, of which 108 (47%) patients achieved psoriasis remission. The group of patients with active psoriasis (n=122, 53%) contained more men (p=0.023) and scored lower on the 12-item Psoriatic Arthritis Impact of Disease questionnaire (p=0.012). On the Skindex-17 psychosocial subscale, 31% experienced moderate to high impairment and on the symptoms subscale 28% experienced a lot of symptoms. Work productivity did not differ between both groups. CONCLUSIONS: The majority of patients with DAPSA-LDA and active psoriasis after one year has a good HRQoL. However, a proportion of these patients still experiences considerable skin burden. We recommend rheumatologists to continue assessing and treating psoriasis to reduce skin burden in PsA patients who achieved musculoskeletal low disease activity.

A Practical Guide for Assessment of Skin Burden in Patients With Psoriatic Arthritis.

OBJECTIVE: Rheumatologists play a pivotal role in the management of patients with psoriatic arthritis (PsA). Due to time constraints during clinic visits, the skin may not receive the attention needed for optimal patient outcome. Therefore, the aim of this study was to select a set of core questions that can help rheumatologists in daily rheumatology clinical practice to identify patients with PsA with a high skin burden. METHODS: Baseline data from patients included in the Dutch South West Psoriatic Arthritis (DEPAR) cohort were used. Questions were derived from the Skindex-17 and Dermatology Life Quality Index (DLQI) questionnaires. Underlying clusters of questions were identified with an exploratory principal component analysis (PCA) with varimax rotation, after which a 2-parameter logistic model was fitted per cluster. Questions were selected based on their discrimination and difficulty. Subsequently, 2 flowcharts were made with categories of skin burden severity. Clinical considerations were specified per category. RESULTS: In total, 413 patients were included. The PCA showed 2 underlying clusters: a psychosocial domain and a domain assessing physical symptoms. We selected these 2 domains. The psychosocial domain contains 3 questions and specifies 4 categories of skin burden severity. The physical symptoms domain contains 2 questions and categorizes patients in 1 out of 3 categories. CONCLUSION: We have selected a set with a maximum of 5 questions that rheumatologists can easily implement in their consultation to assess skin burden in patients with PsA. This practical guide makes the assessment of skin burden more accessible to rheumatologists and can aid in clinical decision making.

The burden of psoriasis in patients with early psoriatic arthritis.

OBJECTIVES: Psoriasis impacts health-related quality of life (HRQoL) in PsA patients. However, this is not adequately measured with a general HRQoL questionnaire. The aim of this study was to quantify the degree of psoriasis evolution in PsA patients over the first year of follow-up and to evaluate whether the impact of psoriasis on HRQoL can be adequately measured with a dermatology-specific HRQoL questionnaire. METHODS: Data were used from PsA patients in the Dutch south west Early Psoriatic Arthritis cohort. Psoriasis severity was measured with the Psoriasis Area and Severity Index (PASI). Dermatology-specific HRQoL was assessed with the Skindex-17 questionnaire. We used a Sankey diagram to illustrate the evolution of psoriasis severity during the first year of follow-up. To assess the association between psoriasis severity and the symptoms and psychosocial subscale of the Skindex-17, a linear regression analysis with hierarchical variable selection and zero-inflated negative binominal regression analysis were performed, respectively. RESULTS: We included 644 patients; 109 (17%) patients had no psoriasis (PASI = 0), 456 (71%) had mild psoriasis (PASI < 7), 56 (9%) had moderate psoriasis (PASI 7-12) and 23 (4%) had severe psoriasis (PASI > 12). Psoriasis severity did not fluctuate much during the first year. PASI was significantly associated with both subscales of the Skindex-17 at baseline and 12 months. CONCLUSION: Psoriasis severity in PsA patients is mostly mild but impacts HRQoL when measured using a dermatology-specific HRQoL questionnaire. For optimal management of PsA patients, we recommend rheumatologists acquire information on skin burden by using a dermatology-specific HRQoL questionnaire.

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.

Fc gamma receptor binding profile of anti-citrullinated protein antibodies in immune complexes suggests a role for FcγRI in the pathogenesis of synovial inflammation.

OBJECTIVES: Anti-citrullinated protein antibodies (ACPA) are highly specific for rheumatoid arthritis (RA). Here, we studied binding of ACPA-IgG immune complexes (IC) to individual Fc gamma receptors (FcγR) to identify potential effector mechanisms by which ACPA could contribute to RA pathogenesis. METHODS: ACPA-IgG1 and control IgG1(IgG1 depleted of ACPA-IgG1) were isolated from plasma and synovial fluid (SF) of RA patients by affinity chromatography using CCP2 peptides. Subsequently, IC were generated using fluorescently labelled F(ab')2 fragments against the F(ab')2 region of IgG, or by using citrullinated fibrinogen. IC were incubated with FcγR-transfected CHO cell lines or neutrophils from healthy donors. FcγR binding of IC was analysed by flow cytometry in the presence or absence of specific blocking antibodies. RESULTS: ACPA-IgG1 IC predominantly bound to FcγRI and FcγRIIIA on FcγR-transfected CHO cell lines, while much lower binding was observed to FcγRIIA and FcγRIIB. ACPA-IgG1 IC showed reduced binding to FcγRIIIA compared to control IgG1 IC, in line with enhanced ACPA-IgG1 Fc core-fucosylation. Neutrophils activated in vitro to induce de novo expression of FcγRI showed binding of ACPA-IgG IC, and blocking studies revealed that almost 30% of ACPA-IgG IC binding to activated neutrophils was mediated by FcγRI. CONCLUSIONS: Our studies show that ACPA-IgG1 IC bind predominately to activating FcγRI and FcγRIIIA, and highlight FcγRI expressed by activated neutrophils as relevant receptor for these IC. As neutrophils isolated from SF exhibit an activated state and express FcγRI in the synovial compartment, this IC-binding could contribute to driving disease pathogenesis in RA.

Clinical and radiological outcomes of 5-year drug-free remission-steered treatment in patients with early arthritis: IMPROVED study.

OBJECTIVES: To determine the 5-year outcomes of early remission induction therapy followed by targeted treatment aimed at drug-free remission (DFR) in patients with early arthritis. METHODS: In 12 hospitals, 610 patients with early (<2 years) rheumatoid arthritis (RA) or undifferentiated arthritis (UA) started on methotrexate (MTX) 25 mg/week and prednisone (60 mg/day tapered to 7.5 mg/day). Patients not in early remission (Disease Activity Score <1.6 after 4 months) were randomised (single blind) to arm 1, adding hydroxychloroquine 400 mg/day and sulfasalazine 2000 mg/day, or arm 2, switching to MTX plus adalimumab 40 mg/2 weeks. Treatment adjustments over time aimed at DFR. Outcomes were remission percentages, functional ability, toxicity and radiological damage progression after 5 years. RESULTS: After 4 months, 387 patients were in early remission, 83 were randomised to arm 1 and 78 to arm 2. After 5 years, 295/610 (48%) patients were in remission, 26% in sustained DFR (SDFR) (≥1 year) (220/387 (57%) remission and 135/387 (35%) SDFR in the early remission group, 50% remission, 11% SDFR in the randomisation arms without differences between the arms). More patients with UA (37% vs 23% RA, p=0.001) and more anticitrullinated protein antibody (ACPA)-negative patients (37% vs 18% ACPA-positive, p<0.001) achieved SDFR.Overall, mean Health Assessment Questionnaire was 0.6 (0.5), and median (IQR) damage progression was 0.5 (0-2.7) Sharp/van der Heijde points, with only five patients showing progression >25 points in 5 years. CONCLUSIONS: Five years of DFR-steered treatment in patients with early RA resulted in almost normal functional ability without clinically relevant joint damage across treatment groups. Patients who achieved early remission had the best clinical outcomes. There were no differences between the randomisation arms. SDFR is a realistic treatment goal.

Serum inflammatory biomarkers fail to identify early axial spondyloarthritis: results from the SpondyloArthritis Caught Early (SPACE) cohort.

INTRODUCTION: Decreasing the diagnostic delay in axial spondyloarthritis (axSpA) remains a major challenge. Here, we assessed the value of serum inflammatory biomarkers to distinguish early axSpA from other pathologies in a large cohort of patients referred with early back pain. METHODS: Serum c reactive protein (CRP), erythrocyte sedimentation rate (ESR) and calprotectin were determined in the SPondyloArthritis Caught Early (SPACE) cohort (n=310), an early back pain inception cohort. Additionally, explorative serum biomarkers derived from the literature (interleukin-27 (IL-27), human ß-defensin-2 (hBD-2) and lipcolin-2 (LCN-2)) were determined by ELISA in full-blown patients with ankylosing spondylitis (AS) (n=21) and healthy controls (n=20). RESULTS: Serum CRP and ESR levels were not elevated in early axSpA versus 'control' back pain patients. Serum calprotectin was elevated in early axSpA versus controls (p=0.01) but failed to identify early axSpA at the individual level (positive predictive value of 38.7%). As to explorative biomarkers, serum levels of IL-27 were not detectable, and hBD-2 and LCN-2 serum levels were not elevated in full-blown AS versus healthy controls (p=0.572, p=0.562, respectively). Therefore, these markers were not further determined in the SPACE cohort. CONCLUSIONS: None of the candidate serum inflammatory markers were useful as diagnostic markers in the early phase of axSpA.

Is the Site of Back Pain Related to the Location of Magnetic Resonance Imaging Lesions in Patients With Chronic Back Pain? Results From the Spondyloarthritis Caught Early Cohort.

OBJECTIVE: To determine associations between magnetic resonance imaging (MRI) lesions originating from either axial spondyloarthritis (SpA) or from degeneration and pain in patients with chronic back pain of <2 years duration. METHODS: Patients from the Spondyloarthritis Caught Early (SPACE) cohort identified the sites of pain (thoracic, lumbar, buttock). The average MRI scores from 2 readers for axial SpA lesions and from 2 different readers for degenerative lesions were used. Associations between sacroiliac (SI) joint lesions and buttock pain were investigated by logistic regression analysis, and associations between axial SpA or degenerative lesions and pain in the spine (thoracic and lumbar) were investigated using generalized estimating equations. Interactions with sex, age, HLA-B27, and fulfillment of Assessment of SpondyloArthritis international Society (ASAS) criteria were tested. RESULTS: In 348 patients (126 males, 127 fulfilling ASAS criteria, mean age 29.4 years), spinal MRI (and SI joint images in 342) were available. Pain was localized in the thoracic spine (35.9%), the lumbar spine (82.5%), or in the buttock(s) (57.8%). Inflammatory lesions of the SI joint (odds ratio [OR] 1.06; P = 0.04) and erosions of the SI joint in patients <25 years (OR 1.16; P = 0.04) were associated with buttock pain. Axial SpA spinal lesions were not associated with pain. Modic type 1 lesions in patients >35 years (OR 5.19; P = 0.001), high-intensity zone lesions in females not fulfilling ASAS criteria (OR 5.09; P = 0.001), and herniation in various subgroups (OR range 2.07-4.66) were associated with pain. CONCLUSION: Specific degenerative lesions, but not typical axial SpA lesions, of the spine are associated with pain at the same location in some subgroups. Inflammatory lesions in the SI joint are associated with buttock pain.

Synovial fluid mononuclear cells provide an environment for long-term survival of antibody-secreting cells and promote the spontaneous production of anti-citrullinated protein antibodies.

OBJECTIVES: In rheumatoid arthritis (RA), observations point to a crucial role for (autoreactive) B cells in disease pathogenesis. Here, we studied whether cells from the synovial environment impact on the longevity of autoreactive B cell responses against citrullinated antigens. METHODS: Synovial fluid mononuclear cells and peripheral blood mononuclear cells (SFMC/PBMC) were obtained from patients with established RA and assessed for the presence of B cell subpopulations. Cells spontaneously secreting anti-citrullinated protein antibodies (ACPA-IgG) directly ex vivo were detected by antigen-specific Enzyme-Linked ImmunoSpot (ELISpot) assay. SFMC and PBMC were cultured to assess the degree of spontaneous ACPA-IgG secretion. Cells surviving for several weeks were characterised by carboxyfluorescein succinimidyl ester (CFSE) labelling and Ki-67 staining. RESULTS: Cells spontaneously secreting ACPA-IgG were readily detectable in peripheral blood and synovial fluid (SF) of patients with ACPA-positive RA. SFMC showed an up to 200-fold increase in ex vivo ACPA-IgG secretion compared with PBMC despite lower numbers of B cells in SFMC. ELISpot confirmed the presence of spontaneously ACPA-IgG-secreting cells, accounting for up to 50% (median 12%) of all IgG-secreting cells in SF. ACPA-IgG secretion was remarkably stable in SFMC cultures, maintained upon depletion of the CD20+ B cell compartment and detectable for several months. CFSE labelling and Ki-67 staining confirmed the long-term survival of non-dividing plasma cells (PCs). CONCLUSIONS: This study demonstrates a high frequency of differentiated, spontaneously ACPA-IgG-secreting cells in SF. These cells are supported by SFMC for prolonged survival and autoantibody secretion, demonstrating that the synovial compartment is equipped to function as inflammatory niche for PC survival.

Predictive factors of radiological progression after 2†years of remission-steered treatment in early arthritis patients: a post hoc analysis of the IMPROVED study.

OBJECTIVES: To identify predictive factors of radiological progression in early arthritis patients treated by remission-steered treatment. METHODS: In the IMPROVED study, 610 patients with early rheumatoid arthritis (RA) or undifferentiated arthritis (UA) were treated with methotrexate (MTX) and a tapered high dose of prednisone. Patients in early remission (disease activity score (DAS) <1.6 after 4 months) tapered prednisone to zero. Patients not in early remission were randomised to arm 1: MTX plus hydroxychloroquine, sulfasalazine and prednisone, or to arm 2: MTX plus adalimumab. Predictors of radiological progression (≥0.5 Sharp/van der Heijde score; SHS) after 2 years were assessed using logistic regression analysis. RESULTS: Median (IQR) SHS progression in 488 patients was 0 (0-0) point, without differences between RA or UA patients or between treatment arms. In only 50/488 patients, the SHS progression was ≥0.5: 33 (66%) were in the early DAS remission group, 9 (18%) in arm 1, 5 (10%) in arm 2, 3 (6%) in the outside of protocol group. Age (OR (95% CI): 1.03 (1.00 to 1.06)) and the combined presence of anticarbamylated protein antibodies (anti-CarP) and anticitrullinated protein antibodies (ACPA) (2.54 (1.16 to 5.58)) were independent predictors for SHS progression. Symptom duration <12 weeks showed a trend. CONCLUSIONS: After 2 years of remission steered treatment in early arthritis patients, there was limited SHS progression in only a small group of patients. Numerically, patients who had achieved early DAS remission had more SHS progression than other patients. Positivity for both anti-CarP and ACPA and age were independently associated with SHS progression. TRIAL REGISTRATION NUMBERS: ISRCTN Register number 11916566 and EudraCT number 2006 06186-16.

Prevalence of degenerative changes of the spine on magnetic resonance images and radiographs in patients aged 16-45 years with chronic back pain of short duration in the Spondyloarthritis Caught Early (SPACE) cohort.

OBJECTIVES: To determine the prevalence of degenerative changes (DCs) in the spine of young patients with back pain without axial spondyloarthritis (no-axSpA), with possible axSpA (poss-axSpA) and with definite axSpA (axSpA), as shown on MRI and radiographs. METHODS: Whole-spine MRI and cervical and lumbar radiography were performed in patients ≥16 years of age with chronic back pain (≥3 months, ≤2 years, onset <45 years) and potential axSpA (Spondyloarthritis Caught Early cohort). Patients were classified as no-axSpA, poss-axSpA [not fulfilling the Assessment of Spondyloarthritis International Society (ASAS) axSpA criteria] or axSpA (fulfilling ASAS axSpA criteria). Images (MRI and X-rays) were evaluated on the presence of DCs by two independent readers, blinded to clinical and laboratory information as well as to the results of the other imaging modality. In cases of disagreement, a third reader served as adjudicator. A Chi-square test was used to analyse differences between patient groups according to various selected cut-off points (1-3) of individual DCs. RESULTS: Of 274 patients (38% male, mean age: 29 years), 25 (9%) were classified as no-axSpA, 134 (48.9%) as poss-axSpA and 115 (42.0%) as axSpA. Two hundred and forty-five (89%) patients had DCs on MRI [21/25 (84%) no-axSpA, 121/134 (90%) poss-axSpA, 103/115 (90%) axSpA, P = 0.792], range 1-29 (median 5.5), and 121 (44%) patients had DCs on radiographs [13/25 (52%) no-axSpA, 62/134 (46%) poss-axSpA, 48/115 (42%) axSpA, P = 0.261], range 1-11 (median 2). Prevalence of DCs was similar between patient groups. DCs were predominantly found in the lumbar spine. CONCLUSION: Prevalence of DCs was high in this cohort of young patients with short-term chronic back pain, in accordance with the literature. Prevalence of DCs in no-axSpA patients, poss-axSpA patients and axSpA patients was found to be similar.

Patients with chronic back pain of short duration from the SPACE cohort: which MRI structural lesions in the sacroiliac joints and inflammatory and structural lesions in the spine are most specific for axial spondyloarthritis?

OBJECTIVES: To investigate the extent and performance of MRI lesions in the sacroiliac joint (MRI-SI) and spine (MRI-spine) in patients with suspected axial spondyloarthritis (axSpA). METHODS: MRI-SI/spine of patients with chronic back pain (onset <45 years) in the SPondyloArthritis Caught Early (SPACE) cohort were scored by two well-trained readers for inflammation, fatty lesions, erosions, sclerosis/ankylosis and syndesmophytes. MRI performances were tested against the Assessment of Spondyloarthritis international Society (ASAS) axSpA criteria (positive: imaging-arm+ or clinical-arm+; negative: possible axSpA (few spondyloarthritis (SpA) features present) or no SpA). Arbitrary cut-off levels for MRI lesions were set to assure at least 95% specificity (tested in the no SpA group). RESULTS: In total 126 patients were ASAS criteria positive (73 imaging-arm+ (22 by modified New York criteria (mNY)+; 51 by MRI+mNY-); 53 clinical-arm+) and 161 were ASAS criteria negative (89 possible axSpA and 72 no SpA). On MRI-SI (n=287), at least three fatty lesions (or at least three erosions) were seen in 45.5 (63.6)% of mNY+ patients, 15.7 (47.1)% of MRI+mNY- patients and 15.1 (13.2)% of clinical-arm+ patients versus 3.4 (6.7)% of possible axSpA patients and 2.8 (4.2)% of no SpA patients. A combined rule (at least five fatty lesions and/or erosions) performed equally well. Sclerosis and ankylosis were too rare to analyse. On MRI-spine (n=284), at least five inflammatory lesions (or at least five fatty lesions) were seen in 27.3 (18.2)% of mNY+ patients, 13.7 (21.6)% of MRI+mNY- patients and 3.8 (1.9)% of clinical-arm+ patients versus 4.5 (6.7)% of possible SpA patients and 2.9 (4.3)% of no SpA patients. CONCLUSIONS: The presence of (1) at least five fatty lesions and/or erosions on MRI-SI, (2) at least five inflammatory lesions or (3) at least five fatty lesions on MRI-spine allows an acceptable discrimination of axSpA and no SpA, while assuring >95% specificity.

Metric Properties of the SPARCC Score of the Sacroiliac Joints - Data from Baseline, 3-month, and 12-month Followup in the SPACE Cohort.

OBJECTIVE: To evaluate metric properties of the SpondyloArthritis Research Consortium of Canada (SPARCC) score of the sacroiliac (SI) joints. METHODS: Patients with back pain (≥ 3 months, ≤ 2 years, onset < 45 years) were included in the SPACE cohort (SpondyloArthritis Caught Early). Patients with (possible) axial spondyloarthritis had followup visits after 3 and 12 months and were treated according to clinical practice. Magnetic resonance imaging (MRI) of the SI joints (MRI-SI) was scored in 2 independent campaigns (campaign 1: at baseline and 3 months; campaign 2: at baseline, 3 months, and 12 months) by 2 different blinded reader pairs, applying the Assessment of Spondyloarthritis International Society (ASAS) definition (MRI-SI+ vs MRI-SI-; discordant cases were adjudicated by a third reader) and SPARCC score (mean of 2 agreeing readers). Calculations were made for agreement between SPARCC score cutoff values and a consensus judgment of MRI-SI+ (ASAS definition) as external standard, change in SPARCC score, and smallest detectable changes (SDC) over 3 and 12 months. RESULTS: SPARCC score ≥ 2 showed best agreement with MRI-SI+ in both campaigns. Regarding observed changes in relation to SDC, SPARCC score changed in 70/151 patients; 26/70 patients changed > SDC (3.4), of whom 20 patients received stable treatment over 3 months in campaign 1. Over 3 months, 20/68 patients showed changes in SPARCC score; 11/20 > SDC (2.1), of whom 8 patients received stable treatment. Over 1 year, 23/74 patients changed their SPARCC score; 14/23 changed > SDC (2.4), of whom 7 received stable treatment in campaign 2. CONCLUSION: SPARCC score ≥ 2 can be used as surrogate for a consensus judgment of MRI-SI+ (ASAS definition) in clinical trials. The SDC ranged from 2.1-3.4 dependent on reader pair and were close to the proposed minimum important change of 2.5.