Evaluation of the Possibility of Axial Psoriatic Arthritis Patients Meeting Classification Criteria for Axial Spondyloarthritis and Ankylosing Spondylitis.

The objective of the study was to analyze whether axial psoriatic arthritis (axPsA) patients meet classification criteria for axial spondyloarthritis (axSpA) and ankylosing spondylitis (AS). A total of 104 patients (66 men and 38 women) with PsA according to CASPAR criteria were examined, all patients had back pain. Patients were evaluated for presence of inflammatory back pain (IBP) by ASAS criteria. Back pain not meeting the ASAS criteria was taken to be chronic back pain (chrBP). Patients underwent hands, feet and pelvis, cervical spine and lumbar spine X-rays. Erosions, osteolysis, and juxta-articular new bone formation were evaluated. Definite radiographic sacroiliitis (d-rSI) was defined as bilateral grade ≥ 2 or unilateral grade ≥ 3. Nineteen patients without d-rSI underwent sacroiliac joints MRI. Ninety-three patients underwent HLA B27 examination. The number of patients who met the criteria for axSpA (ASAS) and the modified New York (mNY) criteria for AS was determined. IBP was identified in 67 (64.4%) patients; chrBP, in 37 (35.6%) patients; 31 (29.8%) patient were of older age (over 40) at the onset of IBP/chrBP; 57 (58.8%) patients had d-rSI; 6 (31.6%) patients had MRI-SI; syndesmophytes were detected in 57 (58.8%) cases. Among 40 patients without d-rSI, 19 (47.5%) had syndesmophytes. In 38/97 (39.2%) patients d-rSI was detected along with syndesmophytes, while 19/97 (19.6%) patients had isolated d-rSI without spondylitis, and 19/97 (19.6%) patients had isolated syndesmophytes without d-rSI. HLA B27 was present in 28 (30.1%) cases. 51 (55.4%) patients met criteria for axSpA. Forty-one (44.6%) patients did not meet criteria for axSpA; however, 27 (65.9%) of them had syndesmophytes. Forty-eight (48.5%) PsA patients met mNY criteria for AS. Among these patients, a set of specific features was revealed: 18 (37.5%) had no IBP, 18 (37.5%) were of older age (over 40) at the onset of IBP/chrBP, 34 (70.8%) had dactylitis, 38 (79.2%) had erosive polyarthritis, 23 (48.8%) had juxta-articular new bone formation, 14 (30.2%) had osteolysis, 23 (48.9%) had "chunky" non-marginal syndesmophytes, and 40 (82.6%) had nail psoriasis; 28 (66.6%) patients were HLA-B27 negative. Forty-five percent of axPsA patients do not meet criteria for axSpA. Characteristic features have been identified to differentiate axPsA from AS.

Axial spondyloarthritis: new advances in diagnosis and management.

Axial spondyloarthritis (axSpA) is an inflammatory disease of the axial skeleton associated with significant pain and disability. Previously, the diagnosis of ankylosing spondylitis required advanced changes on plain radiographs of the sacroiliac joints. Classification criteria released in 2009, however, identified a subset of patients, under the age of 45, with back pain for more than three months in the absence of radiographic sacroiliitis who were classified as axSpA based on a positive magnetic resonance imaging or HLAB27 positivity and specific clinical features. This subgroup was labeled non-radiographic (nr)-axSpA. These patients, compared with those identified by the older New York criteria, contained a larger percentage of women and demonstrated less structural damage. However, their clinical manifestations and response to biologics were similar to radiographic axSpA. The discovery of the interleukin (IL) IL-23/IL-17 pathway revealed key molecules involved in the pathophysiology of axSpA. This discovery propelled the generation of antibodies directed toward IL-17A, which are highly effective and demonstrate treatment responses in axSpA that are similar to those observed with anti-TNF agents. The finding that agents that block IL-23 were not effective in axSpA came as a surprise and the potential underlying mechanisms underlying this lack of response are discussed. New agents with dual inhibition of the IL-17A and F isoforms and some oral small molecule agents that target the Jak-STAT pathway, have also shown efficacy in axSpA.

Classification Criteria in Axial Spondyloarthritis: What Have We Learned; Where Are We Going?

Spondyloarthritis (SpA) is a chronic inflammatory condition that can have a predominately peripheral or axial presentation. Axial SpA (axSpA) affects the axial skeleton with either radiographic (r-axSpA) or nonradiographic (nr-axSpA) changes. Radiographic changes are a late disease feature and earlier disease stages can be identified by incorporating other imaging methods. The diagnosis of axSpA is a clinical diagnosis and classification criteria are not aimed to be diagnostic tools. The split between r-axSpA and nr-axSpA is artificial and we should move toward the unifying concept of axSpA. Our understanding of genetics, biomarkers, and immunopathophenotypes will drive further refinement of classification criteria.

Spinal radiographic progression in axial spondyloarthritis and the impact of classification as nonradiographic versus radiographic disease: Data from the Swiss Clinical Quality Management cohort.

OBJECTIVE: To investigate whether spinal radiographic progression relates to structural damage at the sacroiliac level in axial spondyloarthritis (axSpA). METHODS: Patients classified as nonradiographic (nr-) and radiographic (r-) axSpA in the Swiss Clinical Quality Management cohort with radiographs performed every 2 years, scored according to the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS), were included. The relationship between classification status and spinal progression during 2 years was investigated using binomial generalized estimating equations models with adjustment for sex, ankylosing spondylitis disease activity score (ASDAS) and tumour necrosis factor inhibitor treatment. Baseline spinal damage was considered an intermediate variable and included in sensitivity analyses. RESULTS: In total, 88 nr-axSpA and 418 r-axSpA patients contributed to data for 725 radiographic intervals. R-axSpA patients were more frequently male, had a longer disease duration and higher structural damage at baseline. Mean (SD) mSASSS change over 2 years was 0.16 (0.62) units in nr-axSpA and 0.92 (2.78) units in r-axSpA, p = 0.01. Nr-axSpA was associated with a significantly lower progression in 2 years (defined as an increase in ≥2 mSASSS units) in adjusted analyses (OR 0.33, 95%CI 0.13; 0.83), confirmed with progression defined as the formation of ≥1 syndesmophyte. Mediation analyses revealed that sacroiliitis exerted its effect on spinal progression indirectly by being associated with the appearance of a first syndesmophyte (OR 0.09, 95%CI 0.02; 0.36 for nr-axSpA vs r-axSpA). Baseline syndesmophytes were predictors of further progression. CONCLUSION: Spinal structural damage is mainly restricted to patients with r-axSpA, leading to relevant prognostic and therapeutic implications.

The bone mineral density of hip joint was reduced in the initial stage of ankylosing spondylitis?

The osteoporosis was common complication of ankylosing spondylitis (AS), but it was frequently unrecognized in the initial stage of the disease. This study was to compare areal bone mineral density (BMD) of hip joints in early AS patients with that in healthy controls, to explore the progress of bone loss in cortex and spongiosa in early AS.Quantitative computed tomography (QCT) of hip was performed in 60 AS patients (modified New York criteria for AS, with grade 2 sacroiliitis in computed tomography) and 57 healthy controls. The QCT measurements of AS patients were compared with the measurements of healthy controls.The AS patients had lower areal BMD in cortical bone and total bone of proximal femur in early AS patients (P < .01), than the controls. But there were not significant different of areal BMD in spongiosa of proximal femur between the early AS patients and healthy controls. Strong correlations were found between body mass index BMI, areal BMD in cortical bone (rs = 0.410, P < .001; rs = 0.422, P < .001) and total bone (rs = 0.368, P < .001; rs = 0.266, P = .003) both in AS patients and healthy controls.The results indicate that osteopenia/osteoporosis is general in early stage of AS. What is more, the osteopenia/osteoporosis in cortex is earlier than in spongiosa of proximal femur in early AS.

Identification of Axial Spondyloarthritis Patients in a Large Dataset: The Development and Validation of Novel Methods.

OBJECTIVE: Observational axial spondyloarthritis (axSpA) research in large datasets has been limited by a lack of adequate methods for identifying patients with axSpA, because there are no billing codes in the United States for most subtypes of axSpA. The objective of this study was to develop methods to accurately identify patients with axSpA in a large dataset. METHODS: The study population included 600 chart-reviewed veterans, with and without axSpA, in the Veterans Health Administration between January 1, 2005, and June 30, 2015. AxSpA identification algorithms were developed with variables anticipated by clinical experts to be predictive of an axSpA diagnosis [demographics, billing codes, healthcare use, medications, laboratory results, and natural language processing (NLP) for key SpA features]. Random Forest and 5-fold cross validation were used for algorithm development and testing in the training subset (n = 451). The algorithms were additionally tested in an independent testing subset (n = 149). RESULTS: Three algorithms were developed: Full algorithm, High Feasibility algorithm, and Spond NLP algorithm. In the testing subset, the areas under the curve with the receiver-operating characteristic analysis were 0.96, 0.94, and 0.86, for the Full algorithm, High Feasibility algorithm, and Spond NLP algorithm, respectively. Algorithm sensitivities ranged from 85.0% to 95.0%, specificities from 78.0% to 93.6%, and accuracies from 82.6% to 91.3%. CONCLUSION: Novel axSpA identification algorithms performed well in classifying patients with axSpA. These algorithms offer a range of performance and feasibility attributes that may be appropriate for a broad array of axSpA studies. Additional research is required to validate the algorithms in other cohorts.

Incorporating natural language processing to improve classification of axial spondyloarthritis using electronic health records.

OBJECTIVES: To develop classification algorithms that accurately identify axial SpA (axSpA) patients in electronic health records, and compare the performance of algorithms incorporating free-text data against approaches using only International Classification of Diseases (ICD) codes. METHODS: An enriched cohort of 7853 eligible patients was created from electronic health records of two large hospitals using automated searches (⩾1 ICD codes combined with simple text searches). Key disease concepts from free-text data were extracted using NLP and combined with ICD codes to develop algorithms. We created both supervised regression-based algorithms-on a training set of 127 axSpA cases and 423 non-cases-and unsupervised algorithms to identify patients with high probability of having axSpA from the enriched cohort. Their performance was compared against classifications using ICD codes only. RESULTS: NLP extracted four disease concepts of high predictive value: ankylosing spondylitis, sacroiliitis, HLA-B27 and spondylitis. The unsupervised algorithm, incorporating both the NLP concept and ICD code for AS, identified the greatest number of patients. By setting the probability threshold to attain 80% positive predictive value, it identified 1509 axSpA patients (mean age 53 years, 71% male). Sensitivity was 0.78, specificity 0.94 and area under the curve 0.93. The two supervised algorithms performed similarly but identified fewer patients. All three outperformed traditional approaches using ICD codes alone (area under the curve 0.80-0.87). CONCLUSION: Algorithms incorporating free-text data can accurately identify axSpA patients in electronic health records. Large cohorts identified using these novel methods offer exciting opportunities for future clinical research.

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.

Nonradiographic axial spondyloarthritis: clinical and therapeutic relevance.

Current classification criteria for axial spondyloarthritis (axSpA) provide for the inclusion of patients with a wide range of presentations and manifestations. While not considered a formal subclassification, patients are often divided into radiographic or nonradiographic axSpA based on the presence or absence of radiographic sacroiliitis. This review will focus on nonradiographic axSpA and will discuss clinical manifestations of disease that distinguish, or in many cases do not distinguish, this entity from other individuals with axSpA. This review will also cover treatment paradigms for nonradiographic axSpA, particularly the use of biologic therapies, where current data suggest that nonradiographic disease should be managed largely the same as radiographic disease, or classical ankylosing spondylitis.

Axial spondyloarthritis classification criteria: the debate continues.

PURPOSE OF REVIEW: The Assessment of Spondyloarthritis International Society (ASAS) axial spondyloarthritis (axSpA) classification criteria marked a major step forward in SpA research, distinguishing axial from peripheral disease, and allowing earlier identification through MRI. This facilitated all aspects of research including epidemiology, therapeutics and patient outcomes. RECENT FINDINGS: The ASAS axSpA classification criteria have been applied broadly in research, and were validated in a recent meta-analysis of international studies. Concerns arose because of clinical differences between the clinical and imaging arms, which imply different risk for radiographic progression, and perform differently in validation studies. Low specificity of the MRI finding of sacroiliac joint bone marrow edema may lead to misclassification in populations with low axSpA prevalence. We suggest methodology to improve upon the criteria, including rigorous assessment of potential candidate criteria sets, discrete choice experiments to allow consideration of feature weights, and validation. Separately, assessment of structural and inflammatory MRI abnormalities should be performed to refine the MRI definition of sacroiliitis. SUMMARY: The debate regarding the validation and modification of the ASAS axSpA classification criteria should lead to international efforts to build upon the gains made by these criteria, to further refine the axSpA population definitions for research and ultimately improve patient outcomes.

Axial spondyloarthritis.

The term axial spondyloarthritis covers both patients with non-radiographic and radiographic axial spondyloarthritis, which is also termed ankylosing spondylitis. The disease usually starts in the third decade of life with a male to female ratio of two to one for radiographic axial spondyloarthritis and of one to one for non-radiographic axial spondyloarthritis. More than 90% heritabilty has been estimated, the highest genetic association being with HLA-B27. The pathogenic role of HLA-B27 is still not clear although various hypotheses are available. On the basis of evidence from trials the cytokines tumour necrosis factor (TNF)-α and interleukin-17 appear to have a relevant role in pathogenesis. The mechanisms of interaction between inflammation and new bone formation is still not completely understood but clarification will be important for the prevention of long-term structural damage of the bone. The development of new criteria for classification and for screening of patients with axial spondyloarthritis have been crucial for the early indentification and treatment of such patients, with MRI being the most important existing imaging method. Non-steroidal anti-inflammatory drugs and TNF blockers are effective therapies. Blockade of interleukin-17 is a new and relevant treatment option.

Can we use structural lesions seen on MRI of the sacroiliac joints reliably for the classification of patients according to the ASAS axial spondyloarthritis criteria? Data from the DESIR cohort.

OBJECTIVES: Investigating the utility of adding structural lesions seen on MRI of the sacroiliac joints to the imaging criterion of the Assessment of SpondyloArthritis (ASAS) axial SpondyloArthritis (axSpA) criteria and the utility of replacement of radiographic sacroiliitis by structural lesions on MRI. METHODS: Two well-calibrated readers scored MRI STIR (inflammation, MRI-SI), MRI T1-w images (structural lesions, MRI-SI-s) and radiographs of the sacroiliac joints (X-SI) of patients in the DEvenir des Spondyloarthrites Indifférenciées Récentes cohort (inflammatory back pain: ≥3 months, <3 years, age <50). A third reader adjudicated MRI-SI and X-SI discrepancies. Previously proposed cut-offs for a positive MRI-SI-s were used (based on <5% prevalence among no-SpA patients): erosions (E) ≥3, fatty lesions (FL) ≥3, E/FL ≥5. Patients were classified according to the ASAS axSpA criteria using the various definitions of MRI-SI-s. RESULTS: Of the 582 patients included in this analysis, 418 fulfilled the ASAS axSpA criteria, of which 127 patients were modified New York (mNY) positive and 134 and 75 were MRI-SI-s positive (E/FL≥5) for readers 1 and 2, respectively. Agreement between mNY and MRI-SI-s (E/FL≥5) was moderate (reader 1: κ: 0.39; reader 2: κ: 0.44). Using the E/FL≥5 cut-off instead of mNY classification did not change in 478 (82.1%) and 469 (80.6%) patients for readers 1 and 2, respectively. Twelve (reader 1) or ten (reader 2) patients would not be classified as axSpA if only MRI-SI-s was performed (in the scenario of replacement of mNY), while three (reader 1) or six (reader 2) patients would be additionally classified as axSpA in both scenarios (replacement of mNY and addition of MRI-SI-s). Similar results were seen for the other cut-offs (E≥3, FL≥3). CONCLUSIONS: Structural lesions on MRI can be used reliably either as an addition to or as a substitute for radiographs in the ASAS axSpA classification of patients in our cohort of patients with short symptom duration.

Imaging Scoring Methods in Axial Spondyloarthritis.

Inflammatory and chronic structural changes are objective signs of axial spondyloarthritis. In the sacroiliac joints (SIJs), inflammation (sacroiliitis) can be visualized as bone marrow edema, whereas chronic structural changes are visualized as fat metaplasia, erosions, sclerosis, or ankylosis in the area of the SIJ. In the spine, bone marrow edema in the vertebral bodies represents spondylitis but can also affect the facet and the costovertebral and costotransverse joints (arthritis), whereas structural changes are visualized as fat metaplasia, sclerosis or syndesmophytes and ankylosis at the vertebral edges.

[German translation and cross-cultural adaptation of the ASAS health index : An ICF-based instrument for documentation of functional ability in patients with ankylosing spondylitis]. / Deutsche Übersetzung und krosskulturelle Adaptation des ASAS-Gesundheitsindex : Ein ICF-basiertes Instrument zur Erfassung der Funktionsfähigkeit von Patienten mit ankylosierender Spondylitis.

Documentation of the severity of the disease in patients with spondyloarthritis (SpA) can represent a clinical challenge, especially as the course of SpA can be very different. Patients with SpA often complain of symptoms, such as pain, fatigue and stiffness as well as limitations in mental functions and social participation. This wide range of functional impairments could so far only be insufficiently documented and not with one single measurement instrument. Despite various attempts in recent years, experts could not reach agreement on a definition of the severity and documentation of the extent of the severity. This was the starting point for the development of the ASAS health index presented here, which initially focused on patients with ankylosing spondylitis (AS). This questionnaire serves to document the health and functional ability of patients with AS and has been available since 2015 as the original english version of the ASAS health index together with the accompanying environmental factors set. This article describes the German translation and transcultural adaptation of the ASAS health index and the accompanying environmental factors set.

[MRI of axial spondyloarthritis: diagnostic role and pitfalls]. / IRM dans le diagnostic des spondyloarthrites axiales: utilité et pièges diagnostiques.

MRI has become a major tool for the diagnosis of axial spondyloarthritis and provides objective signs based on which therapy can be initiated. In clinical practice, ASAS classification criteria are often applied for the diagnosis of spondyloarthritis at a pre-radiographic stage. However, MRI signs of spondyloarthritis as stated in ASAS criteria lack specificity, and can be encountered in a wide array of diagnoses, in particular degenerative and mechanical conditions. In this article, we will review the role of MRI in the diagnosis and classification of spondyloarthritis, general technical considerations, the elementary MRI signs of axial spondyloarthritis, as well as diagnostic pitfalls. We also provide a practical approach on how to avoid overdiagnosis of spondyloarthritis and to improve the diagnostic value of MRI.

The term 'non-radiographic axial spondyloarthritis' is much more important to classify than to diagnose patients with axial spondyloarthritis.

The term axial spondyloarthritis (axSpA) now is used frequently to describe patients with predominantly axial symptoms who fit into the spectrum of a well-recognised rheumatic disease that continues to be known as ankylosing spondylitis (AS). The 2009 Assessment of SpondyloArthritis international Society (ASAS) classification criteria, developed to identify patients with early or atypical disease which could not be classified by the 1984 modified New York (mNY) criteria for AS, have led to a differentiation between non-radiographic axial spondyloarthritis (nr-axSpA) and radiographic axSpA, which is largely synonymous with AS. The main reason to distinguish between these ends of the spectrum of axSpA was that tumor necrosis factor (TNF) inhibitors (TNFi) approved for AS could obtain additional labelling for nr-axSpA and be used to treat all patients manifesting clinical features of axSpA. These two terms are distinguished by the degree of 'radiographic sacroiliitis' assessed by conventional radiography, according to the 1984 mNY criteria for AS. Since this differentiation has been shown to be not very reliable, we argue that the terms nr-axSpA and AS should only be used for classification of patients with axSpA and not as separate diagnoses. Therefore, we propose that only the term axSpA be used to diagnose patients, unless there is a meaningful medical reason to differentiate nr-axSpA from AS. The available data justify performing randomised controlled trials designed to obtain regulatory approval for therapeutic agents in patients across the entire spectrum of axSpA.

Comparison of patients with ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA) from a single rheumatology clinic in New Delhi.

AIM: Comparison of ankylosing spondylitis (AS) with non-radiographic axial spondyloarthritis (nr-axSpA) classified with the recent ASsessment of spondyloArthritis International Society (ASAS) criteria. PATIENTS & METHODS: This study included 288 patients clinically diagnosed as having spondyloarthritis (SpA) where a satisfactory radiograph of sacroiliac (S-I) joints was available. The AS and the nr-axSpA groups were compared for the various SpA-related variables. RESULTS: Of 288 axSpA patients, there were 187 with AS. Of the remaining 101 patients without radiographic sacroiliitis, S-I joint magnetic resonance imaging (MRI) was available in 72; 54 of them showed active sacroiliitis thus classified as nr-axSpA according to the ASAS criteria. The remaining 18 patients with normal MRI and the other 29 patients without MRI of the S-I joints (total 47 patients), were classified as nr-axSpA using the 'clinical arm' of the ASAS criteria. On comparing the 187 AS with 101 patients in the nr-axSpA group, the AS group showed significantly more males, longer disease duration, more axial symptoms at disease onset, higher Bath Ankylosing Spondylitis Metrology Index and more syndesmophytes. Biologicals were offered significantly more often to the AS group but methotrexate as monotherapy or in combination with other disease-modifying anti-rheumatic drugs was offered more often in nr-axSpA group. There was no statistically significant difference between AS and nr-axSpA in other SpA parameters. CONCLUSION: The differences brought out between AS and nr-axSpA groups show that they may not be the same disease. A prospective long-term follow-up of large cohorts may help in clarifying if nr-axSpA is simply an early stage in the spectrum of SpA evolving into AS over time or is there inherent difference between them.

Summary of Sensitivity and Specificity for Psoriatic Arthritis in a South African Cohort according to Classification Criteria.

OBJECTIVE: To evaluate the sensitivity and specificity of the classification criteria for psoriatic arthritis (PsA) in a South African cohort. METHODS: Data from consecutive patients with PsA and other chronic inflammatory arthritides were collected prospectively. Subjects were classified according to the classification criteria. The sensitivity and specificity in each group of patients were compared with a clinical diagnosis made by a rheumatologist. RESULTS: The European Spondylarthropathy Study Group criteria exhibited the lowest sensitivity followed by the Moll and Wright criteria. The sensitivity and specificity of the ClASsification for Psoriatic ARthritis (CASPAR) criteria were 98.4% and 99.7%, respectively. CONCLUSION: The CASPAR criteria were evaluated in our cohort and they performed well.