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.

Treatment decisions in axial spondyloarthritis daily clinical practice are more than treat-to-target.

OBJECTIVE: 'Treat-to-target principles' are advised for axial spondyloarthritis (axSpA), although a clear target is not yet defined and targets do not always reflect inflammation. Treat-to-target use and motives for treatment choices in clinics are unknown. Therefore, we studied the presence of residual disease activity according physician's opinion, patient's opinion and composite indices and compared them to the subsequent treatment decisions. METHODS: This cross-sectional multicentre study included 249 patients with a clinical diagnosis of axSpA ≥6 months. Remission and low disease activity according to the BASDAI (<1.9 and <3.5, respectively) and physician's and patient's opinion were assessed. Questionnaires included patient-reported outcomes and patients and physicians completed questions regarding treatment decisions. RESULTS: A total of 115/249 (46%) patients were in remission according to the physician and 37% (n = 43) of these patients reached remission according to the BASDAI. In 51/83 (60%) of the patients with residual disease activity according to the physician and a BASDAI >3.5 the treatment was left unchanged, either because of low disease activity as rated by the physician [n = 15 (29%)] or because of a combination of low disease activity with non-inflammatory complaints or comorbidities [n = 11 (25%)]. Retrospective treat-to-target evaluations showed that treatments were most frequently intensified in patients with arthritis or inflammatory back pain and less often in patients with other (non-inflammatory) musculoskeletal comorbidities. CONCLUSION: This study shows that physicians do not always strictly apply treat-to-target in case of residual disease activity in axSpA. Usually, they accept low disease activity as satisfactory.

Cut-Offs for Disease Activity States in Axial Spondyloarthritis With Ankylosing Spondylitis Disease Activity Score (ASDAS) Based on C-Reactive Protein and ASDAS Based on Erythrocyte Sedimentation Rate: Are They Interchangeable?

OBJECTIVE: Ankylosing Spondylitis Disease Activity Score based on C-reactive protein (ASDAS-CRP) is recommended over ASDAS based on erythrocyte sedimentation rate (ASDAS-ESR) to assess disease activity in axial spondyloarthritis (axSpA). Although ASDAS-CRP and ASDAS-ESR are not interchangeable, the same disease activity cut-offs are used for both. We aimed to estimate optimal ASDAS-ESR values corresponding to the established ASDAS-CRP cut-offs (1.3, 2.1, and 3.5) and investigate the potential improvement of level of agreement between ASDAS-ESR and ASDAS-CRP disease activity states when applying these estimated cut-offs. METHODS: We used data from patients with axSpA from 9 European registries initiating a tumor necrosis factor inhibitor. ASDAS-ESR cut-offs were estimated using the Youden index. The level of agreement between ASDAS-ESR and ASDAS-CRP disease activity states was compared against each other. RESULTS: In 3664 patients, mean ASDAS-CRP was higher than ASDAS-ESR at both baseline (3.6 and 3.4, respectively) and aggregated follow-up at 6, 12, or 24 months (1.9 and 1.8, respectively). The estimated ASDAS-ESR values corresponding to the established ASDAS-CRP cut-offs were 1.4, 1.9, and 3.3. By applying these cut-offs, the proportion of discordance between disease activity states according to ASDAS-ESR and ASDAS-CRP decreased from 22.93% to 19.81% in baseline data but increased from 27.17% to 28.94% in follow-up data. CONCLUSION: We estimated the optimal ASDAS-ESR values corresponding to the established ASDAS-CRP cut-off values. However, applying the estimated cut-offs did not increase the level of agreement between ASDAS-ESR and ASDAS-CRP disease activity states to a relevant degree. Our findings did not provide evidence to reject the established cut-off values for ASDAS-ESR.

Gender-specific differences in patients with psoriatic arthritis receiving ustekinumab or tumour necrosis factor inhibitor: real-world data.

OBJECTIVE: Investigate effects of gender on disease characteristics and treatment impact in patients with PsA. METHODS: PsABio is a non-interventional European study in patients with PsA starting a biological DMARD [bDMARD; ustekinumab or TNF inhibitor (TNFi)]. This post-hoc analysis compared persistence, disease activity, patient-reported outcomes and safety between male and female patients at baseline and 6 and 12 months of treatment. RESULTS: At baseline, disease duration was 6.7 and 6.9 years for 512 females and 417 males respectively. Mean (95% CI) scores for females vs males were: clinical Disease Activity Index for Psoriatic Arthritis (cDAPSA), 32.3 (30.3, 34.2) vs 26.8 (24.8, 28.9); HAQ-Disability Index (HAQ-DI), 1.3 (1.2, 1.4) vs 0.93 (0.86, 0.99); total PsA Impact of Disease-12 (PsAID-12) score, 6.0 (5.8, 6.2) vs 5.1 (4.9, 5.3), respectively. Improvements in scores were smaller in female than male patients. At 12 months, 175/303 (57.8%) female and 212/264 (80.3%) male patients achieved cDAPSA low disease activity, 96/285 (33.7%) and 137/247 (55.5%), achieved minimal disease activity (MDA), respectively. HAQ-DI scores were 0.85 (0.77, 0.92) vs 0.50 (0.43, 0.56), PsAID-12 scores 3.5 (3.3, 3.8) vs 2.4 (2.2, 2.6), respectively. Treatment persistence was lower in females than males (P ≤ 0.001). Lack of effectiveness was the predominant reason to stop, irrespective of gender and bDMARD. CONCLUSIONS: Before starting bDMARDs, females had more severe disease than males and a lower percentage reached favourable disease states, with lower persistence of treatment after 12 months. A better understanding of the mechanisms underlying these differences may improve therapeutic management in females with PsA. TRIAL REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov, NCT02627768.

[18F]Fluoride PET provides distinct information on disease activity in ankylosing spondylitis as compared to MRI and conventional radiography.

PURPOSE: To relate [18F]fluoride uptake on PET with abnormalities on magnetic resonance imaging (MRI) and conventional radiography (CR) in ankylosing spondylitis (AS) patients. METHODS: Ten clinically active AS patients (female 6/10, age 38 ± 11 years) were included, and both spine and SI-joints were examined. PET scans were dichotomously scored for enhanced [18F]fluoride uptake, MRI scans were scored for fatty lesions, erosions, ankylosis, and bone marrow edema (BME), and CR was scored for erosions, syndesmophytes, and ankylosis. The overlap of lesions across all modalities was evaluated through univariate and multivariate analyses using a generalized mixed model. RESULTS: In the spine, 69 lesions with enhanced [18F]fluoride uptake, 257 MRI lesions, and 88 CR lesions were observed. PET lesions were mostly located in costovertebral and facet joints, outside the field of view (FOV) of the MRI and CR. However, PET lesions inside the FOV of MRI and CR partially showed no abnormality on MRI and CR. In lesions with abnormalities on multiple modalities, both univariate and multivariate analysis showed that PET activity had the strongest association with BME on MRI and ankylosis on CR. In the SI joints, 15 lesions (75%) with PET uptake were found, with 87% showing abnormalities on MRI and CR. CONCLUSION: [18F]fluoride PET lesions are often found outside the scope of MRI and CR, and even in the same location show only partial overlap with abnormalities on MRI (especially BME) and CR (especially ankylosis). This suggests that [18F]fluoride PET partially visualizes aspects of AS separate from MRI and CR, providing novel information. CLINICAL TRIAL REGISTRATION: NL43223.029.13 registered at 02-05-2013.  https://www.toetsingonline.nl/to/ccmo_search.nsf/fABRpop?readform&unids=C1257BA2002CC066C1257B4E0049A65A.

18F-sodium fluoride PET-CT visualizes both axial and peripheral new bone formation in psoriatic arthritis patients.

PURPOSE: As bone formation is associated with psoriatic arthritis (PsA), positron emission tomography (PET) using a 18F-Fluoride tracer may enable sensitive detection of disease activity. Our primary aim was to determine the feasibility of whole-body 18F-sodium fluoride PET-CT in clinically active PsA patients to depict new bone formation (as a reflection of disease activity) at peripheral joints and entheses. Our secondary aim was to describe 18F-sodium fluoride findings in the axial skeleton. METHODS: Sixteen patients (female 10/16, age 50.6 ± 8.9 years) with PsA fulfilling CASPAR criteria or with a clinical diagnosis of PsA according to the treating rheumatologist and with ≥ 1 clinically active enthesitis site were included. Of each patient, a whole-body 18F-sodium fluoride PET-CT scan was performed. All scans were scored for PET-positive lesions at peripheral joints, enthesis sites and the spine. Clinical disease activity was assessed by swollen/tender joint count 44, enthesitis according to MASES and SPARCC scores. RESULTS: Out of 1088 evaluated joints, 109 joints showed PET enhancement, mainly in the interphalangeal and metatarsal joints of the feet (14/109, 12.9%) and the distal interphalangeal joints of the hands (14/109, 12.9%). PET positivity was found at 44/464 enthesis sites, mainly at the patella tendon insertion (11/44, 25%) and quadriceps tendon insertion (10/44, 22.7%). Of the PET-positive joints and enthesis sites, respectively 18.2% and 29.5% were clinically positive; 81.8% and 70.5% of the PET-positive joints and entheses respectively were clinically asymptomatic. In 11 patients, ≥ 1 axial PET-positive lesion was observed, mainly in the cervical spine. CONCLUSIONS: New molecular bone formation was observed on 18F-sodium fluoride PET-CT scans, in all domains in which PsA disease activity can be observed, with a substantial part showing no clinical symptoms. CLINICAL TRIAL REGISTRATION: EudraCT: 2017-004,850-40, registered on 13 December 2017.

The impact of a csDMARD in combination with a TNF inhibitor on drug retention and clinical remission in axial spondyloarthritis.

OBJECTIVES: Many axial spondylarthritis (axSpA) patients receive a conventional synthetic DMARD (csDMARD) in combination with a TNF inhibitor (TNFi). However, the value of this co-therapy remains unclear. The objectives were to describe the characteristics of axSpA patients initiating a first TNFi as monotherapy compared with co-therapy with csDMARD, to compare one-year TNFi retention and remission rates, and to explore the impact of peripheral arthritis. METHODS: Data was collected from 13 European registries. One-year outcomes included TNFi retention and hazard ratios (HR) for discontinuation with 95% CIs. Logistic regression was performed with adjusted odds ratios (OR) of achieving remission (Ankylosing Spondylitis Disease Activity Score (ASDAS)-CRP < 1.3 and/or BASDAI < 2) and stratified by treatment. Inter-registry heterogeneity was assessed using random-effect meta-analyses, combined results were presented when heterogeneity was not significant. Peripheral arthritis was defined as ≥1 swollen joint at baseline (=TNFi start). RESULTS: Amongst 24 171 axSpA patients, 32% received csDMARD co-therapy (range across countries: 13.5% to 71.2%). The co-therapy group had more baseline peripheral arthritis and higher CRP than the monotherapy group. One-year TNFi-retention rates (95% CI): 79% (78, 79%) for TNFi monotherapy vs 82% (81, 83%) with co-therapy (P < 0.001). Remission was obtained in 20% on monotherapy and 22% on co-therapy (P < 0.001); adjusted OR of 1.16 (1.07, 1.25). Remission rates at 12 months were similar in patients with/without peripheral arthritis. CONCLUSION: This large European study of axial SpA patients showed similar one-year treatment outcomes for TNFi monotherapy and csDMARD co-therapy, although considerable heterogeneity across countries limited the identification of certain subgroups (e.g. peripheral arthritis) that may benefit from co-therapy.

European bio-naïve spondyloarthritis patients initiating TNF inhibitor: time trends in baseline characteristics, treatment retention and response.

OBJECTIVES: To investigate time trends in baseline characteristics and retention, remission and response rates in bio-naïve axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA) patients initiating TNF inhibitor (TNFi) treatment. METHODS: Prospectively collected data on bio-naïve axSpA and PsA patients from routine care in 15 European countries were pooled. Three cohorts were defined according to year of TNFi initiation: A (1999-2008), B (2009-2014) and C (2015-2018). Retention, remission and response rates were assessed at 6, 12 and 24 months. RESULTS: In total, 27 149 axSpA and 17 446 PsA patients were included. Cohort A patients had longer disease duration compared with B and C. In axSpA, cohort A had the largest proportion of male and HLA-B27 positive patients. In PsA, baseline disease activity was highest in cohort A. Retention rates in axSpA/PsA were highest in cohort A and differed only slightly between B and C. For all cohorts, disease activity decreased markedly from 0 to 6 months. In axSpA, disease activity at 24 months was highest in cohort A, where also remission and response rates were lowest. In PsA, remission rates at 6 and 12 months tended to be lowest in cohort A. Response rates were at all time points comparable across cohorts, and less between-cohort disease activity differences were seen at 24 months. CONCLUSION: Our findings indicate that over the past decades, clinicians have implemented more aggressive treatment strategies in spondyloarthritis. This was illustrated by shorter disease duration at treatment initiation, decreased retention rates and higher remission rates during recent years.

Sex differences in disease activity and efficacy of treatment in spondyloarthritis: is body composition the cause?

PURPOSE OF REVIEW: The body composition and fat distribution is different between men and women, with different levels of circulating adipokines. These differences become more evident when suffering from an inflammatory disease, such as spondyloarthritris. In this review, we will explore the influence of obesity, body composition and adipokines on the differences in disease activity, progression and response to treatment, between men and women with spondyloarthritis. RECENT FINDINGS: Obesity, mainly determined by the body fat content, which is higher in women, is related to worse disease activity scores. Men with higher disease activity lose more muscle mass than women. Leptin, which is usually found at higher levels in overweight women, seems to be associated with greater spinal radiographic progression when it rises during the course of the disease. Being a woman and obesity, mainly because of the body fat content, are related to a worse response to TNF-α blockers. SUMMARY: Overlooking biological sex variation in body composition, circulating adipokines and hormonal levels, and the subsequent differences in clinical presentation, may ultimately hamper clinical treatment.

Sex and gender differences in axial spondyloarthritis: myths and truths.

Mounting evidence reveals evident sex differences in physiology, disease presentation and response to medication in axial SpA (axSpA). Unfortunately these data are often neglected in clinical practice and research. In this review, myths that still exist on diagnosis, disease manifestation and drug effectiveness were argued against data of the most recent literature. The aim is to increase awareness of sex differences in the clinical aspects of axSpA.

Treatment response and drug retention rates in 24 195 biologic-naïve patients with axial spondyloarthritis initiating TNFi treatment: routine care data from 12 registries in the EuroSpA collaboration.

OBJECTIVE: To study drug retention and response rates in patients with axial spondyloarthritis (axSpA) initiating a first tumour necrosis factor inhibitor (TNFi). METHODS: Data from 12 European registries, prospectively collected in routine care, were pooled. TNFi retention rates (Kaplan-Meier statistics), Ankylosing Spondylitis Disease Activity Score (ASDAS) Inactive disease (<1.3), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) <40 mm and Assessment of SpondyloArthritis International Society responses (ASAS 20/40) were assessed at 6, 12 and 24 months. RESULTS: A first TNFi was initiated in 24 195 axSpA patients. Heterogeneity of baseline characteristics between registries was observed. Twelve-month retention was 80% (95% CI 79% to 80%), ranging from 71% to 94% across registries. At 6 months, ASDAS Inactive disease/BASDAI<40 rates were 33%/72% (LUNDEX-adjusted: 27%/59%), ASAS 20/40 response rates 64%/49% (LUNDEX-adjusted 52%/40%). In patients initiating first TNFi after 2009, 6097 patients was registered to fulfil ASAS criteria for axSpA, 2935 was registered to fulfil modified New York Criteria for Ankylosing Spondylitis and 1178 patients was registered as having non-radiographic axSpA. In nr-axSpA patients, we observed lower 12-month retention rates (73% (70%-76%)) and lower 6-month LUNDEX adjusted response rates (ASDAS Inactive disease/BASDAI40 20%/50%, ASAS 20/40 45%/33%). For patients initiating first TNFi after 2014, 12-month retention rate, but not 6-month response rate, was numerically higher compared with patients initiating TNFi in 2009-2014. CONCLUSION: A large European database of patients with axSpA initiating a first TNFi treatment in routine care, demonstrated that 27% of patients achieved ASDAS inactive disease after 6 months, while 59% achieved BASDAI <40. Four of five patients continued treatment after 1 year.

MRI lesions in the sacroiliac joints of patients with spondyloarthritis: an update of definitions and validation by the ASAS MRI working group.

OBJECTIVES: The Assessment of SpondyloArthritis international Society (ASAS) MRI working group (WG) was convened to generate a consensus update on standardised definitions for MRI lesions in the sacroiliac joint (SIJ) of patients with spondyloarthritis (SpA), and to conduct preliminary validation. METHODS: The literature pertaining to these MRI lesion definitions was discussed at three meetings of the group. 25 investigators (20 rheumatologists, 5 radiologists) determined which definitions should be retained or required revision, and which required a new definition. Lesion definitions were assessed in a multi-reader validation exercise using 278 MRI scans from the ASAS classification cohort by global assessment (lesion present/absent) and detailed scoring (inflammation and structural). Reliability of detection of lesions was analysed using kappa statistics and the intraclass correlation coefficient (ICC). RESULTS: No revisions were made to the current ASAS definition of a positive SIJ MRI or definitions for subchondral inflammation and sclerosis. The following definitions were revised: capsulitis, enthesitis, fat lesion and erosion. New definitions were developed for joint space enhancement, joint space fluid, fat metaplasia in an erosion cavity, ankylosis and bone bud. The most frequently detected structural lesion, erosion, was detected almost as reliably as subchondral inflammation (κappa/ICC:0.61/0.54 and 0.60/0.83) . Fat metaplasia in an erosion cavity and ankylosis were also reliably detected despite their low frequency (κappa/ICC:0.50/0.37 and 0.58/0.97). CONCLUSION: The ASAS-MRI WG concluded that several definitions required revision and some new definitions were necessary. Multi-reader validation demonstrated substantial reliability for the most frequently detected lesions and comparable reliability between active and structural lesions.

Association of response to TNF inhibitors in rheumatoid arthritis with quantitative trait loci for CD40 and CD39.

OBJECTIVES: We sought to investigate whether genetic effects on response to TNF inhibitors (TNFi) in rheumatoid arthritis (RA) could be localised by considering known genetic susceptibility loci for relevant traits and to evaluate the usefulness of these genetic loci for stratifying drug response. METHODS: We studied the relation of TNFi response, quantified by change in swollen joint counts ( Δ SJC) and erythrocyte sedimentation rate ( Δ ESR) with locus-specific scores constructed from genome-wide assocation study summary statistics in 2938 genotyped individuals: 37 scores for RA; scores for 19 immune cell traits; scores for expression or methylation of 93 genes with previously reported associations between transcript level and drug response. Multivariate associations were evaluated in penalised regression models by cross-validation. RESULTS: We detected a statistically significant association between Δ SJC and the RA score at the CD40 locus (p=0.0004) and an inverse association between Δ SJC and the score for expression of CD39 on CD4 T cells (p=0.00005). A previously reported association between CD39 expression on regulatory T cells and response to methotrexate was in the opposite direction. In stratified analysis by concomitant methotrexate treatment, the inverse association was stronger in the combination therapy group and dissipated in the TNFi monotherapy group. Overall, ability to predict TNFi response from genotypic scores was limited, with models explaining less than 1% of phenotypic variance. CONCLUSIONS: The association with the CD39 trait is difficult to interpret because patients with RA are often prescribed TNFi after failing to respond to methotrexate. The CD39 and CD40 pathways could be relevant for targeting drug therapy.

Antidrug antibody detection for adalimumab depends on the type of assay used: an experimental approach to help clinicians interpret diagnostic data.

OBJECTIVES: To compare different methods of antidrug antibody (ADA) against adalimumab detection in ankylosing spondylitis (AS) patients and the impact of ADA on adalimumab drug levels and mean ASDAS-CRP. METHODS: We used the acid-dissociation-radioimmunoassay (ARIA), antidrug-binding-test (ABT) and a bridging Enzyme-linked Immunosorbent Assay (ELISA) to detect ADA at 4, 12 and 24 weeks of treatment. Patients were divided into groups; all assays negative (All-neg), only ARIA positive (ARIA-only-pos), ARIA and ABT positive, bridging ELISA negative (ARIA/ABT-double-pos) and all assays positive (All-pos). RESULTS: Eighty-three consecutive AS patient were included. At week 4, 18% compared to 11% and 0% of the patients tested positive for ADA in the ARIA, ABT and bridging ELISA, respectively. At week 12 and 24, cumulative 52% and 69% patients tested positive in the ARIA, compared to 27% and 30% patients in the ABT and 2% patients in the bridging ELISA. Adalimumab levels between All-neg and ARIA-only-pos were 9.1 (5.5-12.5) and 8.5 (5.7-12.3). Drug levels differed between ARIA/ABT-double-pos (2.7 (1.3-4.4)) and All-neg (9.1 (5.5-12.5)). All-pos patients had undetectable drug levels. Mean ASDAS-CRP at week 24 differs between All-neg (1.9 (±1.2)), and All-pos (3.8 (±1.9)) and ARIA/ABT-double-pos (2.0 (±1.1)) and All-pos. CONCLUSIONS: The majority of AS patients had detectable ADA against adalimumab in the ARIA. The ARIA detects more ADA compared to the less drug tolerant ABT and bridging ELISA. The clinical relevance depends on the impact on the bio-availability of the drug. A drug level measurement therefore helps to interpret ADA data regardless of type of assay used.

Simultaneous occurrence of ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis: a systematic review.

Objectives: AS and DISH are both spinal ankylosing conditions with a 4-fold increased risk of spinal fractures. The most commonly used criteria for DISH were designed to exclude radiographic signs of spondyloarthritis. However, case reports describing the presence of both conditions exist. In this study, the co-occurrence of AS and DISH were reviewed in the literature to explore the potential need to revise the criteria for DISH. Methods: A search was conducted in Pubmed, Embase, Web of Science and the Cochrane library using the terms 'spondyloarthritis' and 'DISH' and their matching synonyms. Full-text articles describing the coexistence of both conditions in the same patient were included. A quality assessment was performed, and the case descriptions were extracted. Results: Twenty articles describing simultaneous occurrence of AS and DISH in 39 cases were retrieved. All articles were case reports or series of moderate quality. Back or neck pain was present in 97% of the patients (mean age 61.2 years, 90% male) and HLA-B27 was positive in 9/27 documented measurements. Radiographic abnormalities were described in the SI joint (82% AS, 13% DISH) and in the spine (49% AS, 100% DISH). Conclusion: Simultaneous occurrence of AS and DISH has been reported in the literature in at least 39 cases. AS and DISH should not be seen as mutually exclusive. If the results of the current study are confirmed in a large observational study, revision of the current criteria to include the co-existence of both conditions should be considered.

Bone formation in ankylosing spondylitis during anti-tumour necrosis factor therapy imaged by 18F-fluoride positron emission tomography.

Objectives: Excessive bone formation is an important hallmark of AS. Recently it has been demonstrated that axial bony lesions in AS patients can be visualized using 18F-fluoride PET-CT. The aim of this study was to assess whether 18F-fluoride uptake in clinically active AS patients is related to focal bone formation in spine biopsies and is sensitive to change during anti-TNF treatment. Methods: Twelve anti-TNF-naïve AS patients [female 7/12; age 39 years (SD 11); BASDAI 5.5 ± 1.1] were included. 18 F-fluoride PET-CT scans were performed at baseline and in two patients, biopsies were obtained from PET-positive and PET-negative spine lesions. The remaining 10 patients underwent a second 18F-fluoride PET-CT scan after 12 weeks of anti-TNF treatment. PET scans were scored visually by two blinded expert readers. In addition, 18F-fluoride uptake was quantified using the standardized uptake value corrected for individual integrated whole blood activity concentration (SUVAUC). Clinical response to anti-TNF was defined according to a ⩾ 20% improvement in Assessment of SpondyloArthritis international Society criteria at 24 weeks. Results: At baseline, all patients showed at least one axial PET-positive lesion. Histological analysis of PET-positive lesions in the spine confirmed local osteoid formation. PET-positive lesions were found in the costovertebral joints (43%), facet joints (23%), bridging syndesmophytes (20%) and non-bridging vertebral lesions (14%) and in SI joints (75%). After 12 weeks of anti-TNF treatment, 18F-fluoride uptake in clinical responders decreased significantly in the costovertebral (mean SUVAUC -1.0; P < 0.001) and SI joints (mean SUVAUC -1.2; P = 0.03) in contrast to non-responders. Conclusions: 18F-fluoride PET-CT identified bone formation, confirmed by histology, in the spine and SI joints of AS patients and demonstrated alterations in bone formation during anti-TNF treatment.

2016 update of the ASAS-EULAR management recommendations for axial spondyloarthritis.

To update and integrate the recommendations for ankylosing spondylitis and the recommendations for the use of tumour necrosis factor inhibitors (TNFi) in axial spondyloarthritis (axSpA) into one set applicable to the full spectrum of patients with axSpA. Following the latest version of the European League Against Rheumatism (EULAR) Standardised Operating Procedures, two systematic literature reviews first collected the evidence regarding all treatment options (pharmacological and non-pharmacological) that were published since 2009. After a discussion of the results in the steering group and presentation to the task force, overarching principles and recommendations were formulated, and consensus was obtained by informal voting. A total of 5 overarching principles and 13 recommendations were agreed on. The first three recommendations deal with personalised medicine including treatment target and monitoring. Recommendation 4 covers non-pharmacological management. Recommendation 5 describes the central role of non-steroidal anti-inflammatory drugs (NSAIDs) as first-choice drug treatment. Recommendations 6-8 define the rather modest role of analgesics, and disprove glucocorticoids and conventional synthetic disease-modifying antirheumatic drugs (DMARDs) for axSpA patents with predominant axial involvement. Recommendation 9 refers to biological DMARDs (bDMARDs) including TNFi and IL-17 inhibitors (IL-17i) for patients with high disease activity despite the use (or intolerance/contraindication) of at least two NSAIDs. In addition, they should either have an elevated C reactive protein and/or definite inflammation on MRI and/or radiographic evidence of sacroiliitis. Current practice is to start with a TNFi. Switching to another TNFi or an IL-17i is recommended in case TNFi fails (recommendation 10). Tapering, but not stopping a bDMARD, can be considered in patients in sustained remission (recommendation 11). The final two recommendations (12, 13) deal with surgery and spinal fractures. The 2016 Assessment of SpondyloArthritis international Society-EULAR recommendations provide up-to-date guidance on the management of patients with axSpA.

Muscle wasting in male TNF-α blocker naïve ankylosing spondylitis patients: a comparison of gender differences in body composition.

Objective: To assess gender differences in body composition (BC) in a cohort of AS patients naïve to TNF-α blockers. Methods: Patients included fulfilled the Modified New York criteria for AS. Demographic information and disease activity measures (ASDAS and BASDAI) were reported. BC was measured by whole body DXA. Body fat percentage (BF%), fat mass index (FMI), fat free mass index (FFMI) and android/gynoid fat ratio were reported and compared between men and women and with the reference population (percentiles). Results: Seventy consecutive patients were included; 60% were men. Demographic variables were similar, except for dyslipidaemia (57.1% of men; 14.3% of women). Women had significantly more fat (BF%, FMI), and less muscle (FFMI) than men, but below the median of the reference population. Male AS patients had a markedly low FFMI (31.7th percentile) compared with the reference population. In the whole group, after multivariate analysis, an ASDAS CRP >3.5 was related to lower fat free mass content. In men, a significant relationship between having a high disease activity (ASDAS, BASDAI) and lower BF% or FMI percentile was found, but in women it was the opposite. Conclusion: Muscle wasting, measured as low FFMI compared with the reference population, was found in male TNF-α blocker naïve AS patients, especially in those with active disease. Women had higher volumes of body fat than men, but near the median of the reference population. The relationships between fat content and disease activity support the complex association between adipose tissue and inflammation.

Predictive validity of the ASAS classification criteria for axial and peripheral spondyloarthritis after follow-up in the ASAS cohort: a final analysis.

OBJECTIVE: To establish the predictive validity of the Assessment of SpondyloArthritis international Society (ASAS) spondyloarthritis (SpA) classification criteria. METHODS: 22 centres (N=909 patients) from the initial 29 ASAS centres (N=975) participated in the ASAS-cohort follow-up study. Patients had either chronic (>3 months) back pain of unknown origin and age of onset below 45 years (N=658) or peripheral arthritis and/or enthesitis and/or dactylitis (N=251). At follow-up, information was obtained at a clinic visit or by telephone. The positive predictive value (PPV) of the baseline classification by the ASAS criteria was calculated using rheumatologist's diagnosis at follow-up as external standard. RESULTS: In total, 564 patients were assessed at follow-up (345 visits; 219 telephone) with a mean follow-up of 4.4 years (range: 1.9; 6.8) and 70.2% received a SpA diagnosis by the rheumatologist. 335 patients fulfilled the axial SpA (axSpA) or peripheral SpA (pSpA) criteria at baseline and of these, 309 were diagnosed SpA after follow-up (PPV SpA criteria: 92.2%). The PPV of the axSpA and pSpA criteria was 93.3% and 89.5%, respectively. The PPV for the 'clinical arm only' was 88.0% and for the 'clinical arm'±'imaging arm' 96.0%, for the 'imaging arm only' 86.2% and for the 'imaging arm'+/-'clinical arm' 94.7%. A series of sensitivity analyses yielded similar results (range: 85.1-98.2%). CONCLUSIONS: The PPV of the axSpA and pSpA criteria to forecast an expert's diagnosis of 'SpA' after more than 4 years is excellent. The 'imaging arm' and 'clinical arm' of the axSpA criteria have similar predictive validity and are truly complementary.

Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: update by the ASAS MRI working group.

OBJECTIVES: To review and update the existing definition of a positive MRI for classification of axial spondyloarthritis (SpA). METHODS: The Assessment in SpondyloArthritis International Society (ASAS) MRI working group conducted a consensus exercise to review the definition of a positive MRI for inclusion in the ASAS classification criteria of axial SpA. Existing definitions and new data relevant to the MRI diagnosis and classification of sacroiliitis and spondylitis in axial SpA, published since the ASAS definition first appeared in print in 2009, were reviewed and discussed. The precise wording of the existing definition was examined in detail and the data and a draft proposal were presented to and voted on by the ASAS membership. RESULTS: The clear presence of bone marrow oedema on MRI in subchondral bone is still considered to be the defining observation that determines the presence of active sacroiliitis. Structural damage lesions seen on MRI may contribute to a decision by the observer that inflammatory lesions are genuinely due to SpA but are not required to meet the definition. The existing definition was clarified adding guidelines and images to assist in the application of the definition. CONCLUSION: The definition of a positive MRI for classification of axial SpA should continue to primarily depend on the imaging features of 'active sacroiliitis' until more data are available regarding MRI features of structural damage in the sacroiliac joint and MRI features in the spine and their utility when used for classification purposes.