Identifying patients with axial spondyloarthritis in primary care: how useful are items indicative of inflammatory back pain?

A scoping review of triage approaches for the referral of patients with suspected inflammatory arthritis, from primary to rheumatology care

We aimed to (1) identify existing triage approaches for referral of patients with suspected inflammatory arthritis (IA) from primary care physicians (PCP) to rheumatologists, (2) describe their characteristics and methodologies for clinical use, and (3) report their level of validation for use in a publicly funded healthcare system. The comprehensive search strategy of multiple databases up to October 2023 identified relevant literature and focussed on approaches applied at the PCP-Rheumatologist referral stage. Primary, quantitative studies, reported in English were included. Triage approaches were grouped into patient conditions as defined by the authors of the reports, including IA, its subtypes and combinations. 13952 records were identified, 425 full text reviewed and 55 reports of 53 unique studies were included. Heterogeneity in disease nomenclature and study sample pretest probability was found. The number of published studies rapidly increased after 2012. Studies were mostly from Europe and North America, in IA and Axial Spondyloarthritis (AxSpa). We found tools ranging the continuum of development with those best performing, indicated by the area under the receiver operating curve (AUC) >0.8), requiring only patient-reported questions. There were AUCs for some tools reported from multiple studies, these were in the outstanding to excellent range for the Early IA Questionnaire (EIAQ) (0.88 to 0.92), acceptable for the Case Finding AxSpa (CaFaSpa) (0.70 to 0.75), and poor to outstanding for the Psoriasis Epidemiology Screening Tool (PEST) (0.61 to 0.91). Given the clinical urgency to improve rheumatology referrals and considering the good.

Regional Differences in Diagnosis Journey and Healthcare Utilization: Results from the International Map of Axial Spondyloarthritis (IMAS)

INTRODUCTION

To assess differences in the diagnosis journey and access to care in a large sample of patients with axial spondyloarthritis (axSpA) from around the world, included in the International Map of Axial Spondyloarthritis (IMAS).

METHODS

IMAS was a cross-sectional online survey (2017-2022) of 5557 unselected patients with axSpA from 27 countries. Across five worldwide geographic regions, the patient journey until diagnosis and healthcare utilization in the last 12 months prior to survey were evaluated. Univariable and multivariable linear regression was used to analyze factors associated with higher healthcare utilization.

RESULTS

Of 5557 participants in IMAS, the diagnosis took an average of 7.4 years, requiring more than two visits to HCPs (77.7% general practitioner and 51.3% rheumatologist), and more than two diagnostic tests [67.5% performed human leukocyte antigen B27 (HLA-B27), 64.2% x-ray, and 59.1% magnetic resonance imaging (MRI) scans]. North America and Europe were the regions with the highest number of healthcare professional (HCP) visits for diagnosis, while the lowest number of visits was in the Asian region. In the previous 12 months, 94.9% (n = 5272) used at least one healthcare resource, with an average of 29 uses per year. The regions with the highest healthcare utilization were Latin America, Europe, and North America. In the multiple linear regression, factors associated with higher number of healthcare utilization were younger age (b =  - 0.311), female gender (b = 7.736), higher disease activity (b = 1.461), poorer mental health (b = 0.624), greater functional limitation (b = 0.300), greater spinal stiffness (b = 1.527), and longer diagnostic delay (b = 0.104).

CONCLUSION

The diagnosis of axSpA usually takes more than two visits to HCPs and at least 7 years. After diagnosis, axSpA is associated with frequent healthcare resource use. Younger age, female gender, higher disease activity, poorer mental health, greater functional limitation, greater spinal stiffness, and longer diagnostic delay are associated with higher healthcare utilization. Europe and North America use more HCP visits and diagnostic tests before and after diagnosis than the other regions.

[The role of HLA-B27 in the pathogenesis and diagnosis of axial spondyloarthritis : 50 years after discovery of the strong genetic association]

BACKGROUND

The association of the human lymphocyte antigen B27 (HLA-B27) with ankylosing spondylitis (AS), also now called axial spondylarthritis (axSpA), was first described 50 years ago.

OBJECTIVE

This article gives an overview of the available knowledge on the topic.

MATERIAL AND METHODS

This is a narrative review based on the experience of the authors.

RESULTS

The HLA-B27 is a member of the HLA class I family of genes of the major histocompatibility complex (MHC). The prevalence of HLA-B27 in the central European population is approximately 8 %, i.e., the vast majority of carriers of HLA-B27+ remain healthy. The frequency of HLA-B27 shows a decline from north to south. The HLA-B27 explains only 30 % of the genetic burden of axSpA. The prevalence of the disease correlates with the frequency of HLA-B27 in the population, i.e., there are geographic differences. Approximately 60-90 % of patients with axSpA worldwide are HLA-B27+. Some 200 subtypes of HLA-B27 can be differentiated using the polymerase chain reaction (PCR). In Thailand and Sardinia two subtypes were found that are not associated with axSpA. The physiological function of HLA class I molecules is the defence of the organism against microbes. Microbial peptides are presented to the immune system, which can be specifically attacked by CD8+ T‑cells. Genetic polymorphisms of the enzyme endoplasmic reticulum aminopeptidase 1 (ERAP1), which breaks down peptides in the endoplasmic reticulum, are associated only with HLA-B27+ diseases.

DISCUSSION

The pathogenesis of axSpA is unclear but a major hypothesis is that of the arthritogenic peptides. In this it is assumed that potentially pathogenic foreign or autologous peptides can be presented by HLA-B27. If nothing else, HLA-B27 plays an important role in the diagnosis, classification and determination of the severity of axSpA.

Performance of clinical, laboratory and imaging features for diagnosing spondyloarthritis-a systematic literature review and meta-analysis

OBJECTIVE

The Berlin algorithm was developed to help diagnosing axial spondyloarthritis (axSpA), but new studies suggest some features typical of SpA are less specific than previously assumed. Furthermore, evidence is lacking for other SpA subtypes (e.g. peripheral SpA). We aimed to review the evidence on the performance of SpA features for diagnosing each SpA subtype.

METHODS

Systematic literature review of studies reporting the diagnostic performance of ≥ 1 SpA feature in patients with suspected SpA. The external reference was the rheumatologist's diagnosis of SpA. Meta-analysis was performed, separately for each SpA subtype, to estimate pooled sensitivity, specificity, positive (LR+) and negative (LR-) likelihood ratios. Meta-regression assessed the effect of covariates (e.g. feature's prevalence) on each feature's performance.

RESULTS

Of 13 844 articles screened, 46 were included. Sacroiliitis on magnetic resonance imaging, damage on pelvic radiographs and elevated C-reactive protein (CRP) had the best balance between LR+ and LR- (LR + 3.9-17.0, LR- 0.5-0.7) for diagnosing axSpA. HLA-B27 had an LR+ lower than anticipated (LR + =3.1). Inflammatory back pain (IBP) had low LR + (LR+∼1), but substantially decreased the likelihood of axSpA when absent (LR-=0.3). Conversely, peripheral features and extra-musculoskeletal manifestations showed high LR + (LR+ 1.6-5.0), but were as common in axSpA as no-axSpA (LR-∼1). The specificity of most features was reduced in settings when these were highly prevalent. Limited data precluded a detailed analysis on diagnosing other SpA subtypes.

CONCLUSION

Imaging features and CRP have good diagnostic value for axSpA. However, the specificity of other features, especially HLA-B27 and IBP, is lower than previously known.

Diagnostic clinical prediction rules for categorising low back pain: A systematic review

BACKGROUND

Low back pain (LBP) is a common complex condition, where specific diagnoses are hard to identify. Diagnostic clinical prediction rules (CPRs) are known to improve clinical decision-making. A review of LBP diagnostic-CPRs by Haskins et al. (2015) identified six diagnostic-CPRs in derivation phases of development, with one tool ready for implementation. Recent progress on these tools is unknown. Therefore, this review aimed to investigate developments in LBP diagnostic-CPRs and evaluate their readiness for implementation.

METHODS

A systematic review was performed on five databases (Medline, Amed, Cochrane Library, PsycInfo, and CINAHL) combined with hand-searching and citation-tracking to identify eligible studies. Study and tool quality were appraised for risk of bias (Quality Assessment of Diagnostic Accuracy Studies-2), methodological quality (checklist using accepted CPR methodological standards), and CPR tool appraisal (GRade and ASsess Predictive).

RESULTS

Of 5021 studies screened, 11 diagnostic-CPRs were identified. Of the six previously known, three have been externally validated but not yet undergone impact analysis. Five new tools have been identified since Haskin et al. (2015); all are still in derivation stages. The most validated diagnostic-CPRs include the Lumbar-Spinal-Stenosis-Self-Administered-Self-Reported-History-Questionnaire and Diagnosis-Support-Tool-to-Identify-Lumbar-Spinal-Stenosis, and the StEP-tool which differentiates radicular from axial-LBP.

CONCLUSIONS

This updated review of LBP diagnostic CPRs found five new tools, all in the early stages of development. Three previously known tools have now been externally validated but should be used with caution until impact evaluation studies are undertaken. Future funding should focus on externally validating and assessing the impact of existing CPRs on clinical decision-making.

Burden of disease and impact on quality of life in chronic back pain - a comparative cross-sectional study of 150 axial spondyloarthritis and 150 orthopedic back pain patients

Objective

Chronic back pain (CBP) constitutes one of the most common complaints in primary care and a leading cause of disability worldwide. CBP may be of mechanical or inflammatory character and may lead to functional impairment and reduced quality of life. In this study, we aimed to assess and compare burden of disease, functional capacity, quality of life and depressive symptoms in axial spondyloarthritis (axSpA) patients with orthopedic chronic back pain patients (OBP). We further aimed to identify factors associated with quality of life.

Methods

Cross-sectional survey of a cohort of 300 CBP patients including 150 patients from a University Hospital Orthopedic Back Pain Outpatient Clinic with OBP and 150 patients with confirmed axSpA from a University Hospital Rheumatology Outpatient Clinic. Questionnaire-based assessment of pain character (Inflammatory Back Pain, MAIL-Scale), functional status (FFbH, BASFI), quality of life (WHOQOL-Bref) and depressive symptoms (Phq9) and retrospective medical chart analysis.

Results

Both, OBP and axSpA patients reported on average intermediate pain levels of mostly mixed pain character. Both groups demonstrated a reduced health-related quality of life and the presence of depressive symptoms. However, axSpA patients reported a significantly better subjective quality of life, more satisfaction with their health status and better functional capacity compared to OBP patients (all p < 0.001). In a multivariate regression model, depressive symptoms, mechanical back pain, pain level and age were negative predictors of subjective quality of life, whereas functional capacity was a positive predictor.

Conclusion

Chronic back pain was associated with a high morbidity and reduced quality of life regardless of pain character. We identified multiple factors associated with reduced quality of life. Awareness and addressing of these factors may help to overcome unmet needs and improve quality of life for these patients.

Diagnosis Value of Patient Evaluation Components Applicable in Primary Care Settings for the Diagnosis of Low Back Pain: A Scoping Review of Systematic Reviews

Low back pain ranks as the leading cause of years lived with disability worldwide. Although best practice guidelines share a consistent diagnostic approach for the evaluation of patients with low back pain, confusion remains as to what extent patient history and physical examination findings can inform management strategies. The aim of this study was to summarize evidence investigating the diagnostic value of patient evaluation components applicable in primary care settings for the diagnosis of low back pain. To this end, peer-reviewed systematic reviews were searched in MEDLINE, CINAHL, PsycINFO and Cochrane databases from 1 January 2000 to 10 April 2023. Paired reviewers independently reviewed all citations and articles using a two-phase screening process and independently extracted the data. Of the 2077 articles identified, 27 met the inclusion criteria, focusing on the diagnosis of lumbar spinal stenosis, radicular syndrome, non- specific low back pain and specific low back pain. Most patient evaluation components lack diagnostic accuracy for the diagnosis of low back pain when considered in isolation. Further research is needed to develop evidence-based and standardized evaluation procedures, especially for primary care settings where evidence is still scarce.

Extent of axial damage in psoriatic arthritis and spondyloarthritis: comparative data from the BEPAS and (Be-)GIANT multicentre cohorts

BACKGROUND

To examine radiographic axial damage of the sacroiliac joints and spine in patients with psoriatic arthritis (PsA) and spondyloarthritis (SpA) in private and academic Belgian practices.

METHODS

Patients with PsA with clinical diagnosis of PsA and fulfilling the Classification Criteria for Psoriatic Arthritis from the prospective Belgian Epidemiological Psoriatic Arthritis Study and patients with SpA fulfilling the Assessment of SpondyloArthritis international Society classification criteria for SpA originate from the Ghent and BelGian Inflammatory Arthritis and spoNdylitis cohorTs were included in this study. Baseline pelvic and spinal radiographs were analysed by two calibrated readers. Blinded for the origin of the cohort or clinical data readers assessed the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) and modified New York criteria on spinal and pelvic radiographs, respectively. Data were compared between both patient groups.

RESULTS

Of the 525 patients included (312 PsA and 213 SpA), most patients showed normal spinal radiographs: 87.5% of the patients with PsA and 92.0% of the patients with SpA. Patients with SpA with spinal damage show higher mSASSS than the patients with PsA (p<0.05). In patients with PsA, cervical spine is more often affected; 24/33 patients (72.7%) compared with lumbar spine 11/33 (33.3%). While in patients with SpA, syndesmophyte location was more evenly distributed; cervical 9/14 (64.3%) and lumbar 10/14 (71.4%).

CONCLUSION

Minimal radiographic spinal damage was observed in Belgian patients with PsA or SpA. Patients with SpA tend to have higher mSASSS values and more syndesmophytes compared with PsA. Syndesmophytes were more often located in the cervical spine of patients with PsA, while the location was equally distributed in axSpA.

Axial Spondyloarthritis and Diagnostic Challenges: Over-diagnosis, Misdiagnosis, and Under-diagnosis

PURPOSE OF REVIEW

This article aims to review the challenges in axial spondyloarthritis diagnosis and identify the possible contributing factors.

RECENT FINDINGS

The inability to reach an accurate diagnosis in a timely fashion can lead to treatment delays and worse disease outcomes. The lack of validated diagnostic criteria and the misuse of the currently available classification criteria could be contributing. There is also significant inter-reader variability in interpreting images, and the radiologic definitions of axial spondyloarthritis continue to be re-defined to improve their positive predictive value. The role of inflammatory back pain features, serologic biomarkers, genetics, and their diagnostic contribution to axial spondyloarthritis continues to be investigated. There is still a significant amount of delay in the diagnosis of axial spondyloarthritis. Appreciating the factors that contribute to this delay is of utmost importance to close the gap. It is similarly important to recognize other conditions that may present with symptoms that mimic axial spondyloarthritis so that misdiagnosis and wrong treatment can be avoided.

The influence of age on the prevalence of inflammatory and structural MRI lesions in the SIJ of patients with and without axSpA

OBJECTIVE

To compare the influence of age on inflammatory (bone marrow oedema. BME) and structural (fat lesions (FL), erosions and ankylosis) MRI lesions in the SIJ of patients with and without axial spondyloarthritis (axSpA).

METHODS

In a retrospective study, SIJ MRI (STIR/T1 sequences) of consecutive patients with chronic back pain diagnosed with axSpA or non-SpA were evaluated based on SIJ quadrants (SIJ-Q). Two blinded readers evaluated BME and structural lesions. Reader agreement was evaluated for prevalence of MRI lesions related to age.

RESULTS

MRIs of 309 (175 axSpA, 134 non-SpA) patients were evaluated. Their mean age was 38.5 ± 11.4 vs 43.4 ± 13.8 years (y), 67% and 36% were male, CRP 1.6 ± 2.4 vs 1.1 ± 2.1 mg/dl, median symptom duration 48 and 60 months, respectively. SIJ-Q with BME and erosions were significantly more frequent in axSpA vs non-SpA patients independent of age, while this difference was seen for FL only in patients ≥50 y. The proportion of patients with ≥1 or ≥ 3 BME or chronic lesions except for FL increased with age in both groups, and was constantly higher in axSpA vs non-SpA. In univariate analyses, only female sex was significantly associated with more FL.

CONCLUSIONS

The proportion of patients with MRI lesions was high in both, axSpA and non-SpA patients. However, the prevalence of BME and erosions was significantly more frequent in patients with axSpA, was independent of age and also allowed for discrimination. FL occurred more frequently only in older age groups and were less reliable for discrimination vs. non-SpA patients.

Development and test–retest reliability of a screening tool for axial spondyloarthritis

Background

People with axial Spondyloarthritis (axSpA) suffer from lengthy diagnostic delays of ~7 years. The usage of screening tools to identify axSpA patients in primary care can reduce diagnostic delays by facilitating early referral to rheumatologic care. The purpose of this study was to examine the psychometric properties of a potential screening tool for patients with axSpA.

Method

Content validity was evaluated by soliciting feedback from 7 rheumatologists regarding the relevance and content representativeness of the proposed screening questions. For the test-retest study, participants ≥18 years of age with chronic back pain (≥3 months) without a diagnosis of mechanical or inflammatory back pain (n = 91) were e-recruited through ResearchMatch. Participation included completing identical baseline and follow-up questionnaires ~14 days apart. Weighted quadratic kappa was used to measure test-retest reliability between the two ratings of the ordinal scales. Construct validity was examined using exploratory factor analysis (EFA) and items with factor loadings ≥0.6 were extracted. Scale dimensionality and simplified factorial solutions were measured using Kaiser’s criteria (Eigenvalue >1). Cronbach’s alpha was used to measure internal consistency.

Results

Most participants were women, non-Hispanic white, and had at least some college education, with a mean age of 45 years. On average, the age at onset of back pain was 31 years. Eleven questions yielded test–retest reliabilities ranging from 0.6 to 0.76. Results from EFA extracted two factors relating to: 1) how pain affects daily life functioning and 2) whether pain improves with movement. Internal consistency was high for questions evaluating how pain affects life, with a Cronbach’s alpha of 0.81. Following assessment for validity and reliability, the questionnaire was revised to create the 6-item screening tool.

Conclusions

The 6-item SpA-SED screening tool designed to identify potential cases of axSpA was found to have good test–retest reliability and high internal consistency.

Differentiating nonradiographic axial spondyloarthritis from its mimics: a narrative review

Background

Optimal treatment of nonradiographic axial spondyloarthritis depends on accurate and timely diagnosis of the underlying disease; however, patients present with common symptoms that, in the absence of radiographic changes, may confound diagnosis.

Methods and findings

In this narrative review, a PubMed literature search was conducted through January 2021, with no date limits, to identify English-language publications discussing classification of nonradiographic axial spondyloarthritis, with an emphasis on clinical features and presentation, differential diagnoses, and mimics of disease. This review describes the epidemiology, clinical features, and burden of disease of nonradiographic axial spondyloarthritis as it relates to the overall axial spondyloarthritis spectrum and discusses mimics and differential diagnoses of nonradiographic axial spondyloarthritis that should be considered when evaluating patients with suspected nonradiographic axial spondyloarthritis in clinical practice.

Conclusions

Recognition of clinical features of nonradiographic axial spondyloarthritis, along with an understanding of comorbid conditions such as fibromyalgia, allows for differentiation from its mimics. Appropriate diagnosis of nonradiographic axial spondyloarthritis is important for aggressive management of disease to reduce pain, avoid loss of function, and improve quality of life.

Axial Spondyloarthritis in the Chiropractic Care Setting: A Systematic Literature Review

ABSTRACT

Diagnosis of axial spondyloarthritis (axSpA), an immune-mediated inflammatory disease, is commonly associated with chronic inflammatory back pain (IBP) and often occurs years after initial onset of clinical symptoms. Recognition of IBP is important for timely referral of patients with suspected axSpA to a rheumatologist. Patients with all types of back pain are treated in chiropractic care, but the proportion of patients with undiagnosed axSpA is unknown. This systematic literature review investigated the presence of axSpA in patients treated by chiropractors and identified the chiropractor's role in axSpA diagnosis, referral, and management. A PubMed search was conducted using the following search strings: "chiropract*" AND ("sacroiliac" OR "back pain" OR "spondyloarthritis" OR "ankylosing spondylitis"); English language, since 2009; and (chiropractic OR chiropractor) AND (ankylosing spondylitis OR axial spondyloarthritis), with no date limits. Of 652 articles identified in the searches, 27 met the inclusion criteria. Although back pain was identified as a common reason for patients seeking chiropractic care, there was no mention of axSpA, ankylosing spondylitis, or the distinction between mechanical and IBP. Data from relevant articles suggested that the majority of patients seeking chiropractic care have lower back pain, whereas no articles reported axSpA in this patient population. The near absence of any identified articles on axSpA in chiropractic care may be due to underrecognition of axSpA, resulting in delayed rheumatology referral and appropriate management. Better awareness and increased use of validated screening tools could reduce diagnostic delay of axSpA in chiropractic care.

Early identification of axial spondyloarthritis in a multi-ethnic Asian population

INTRODUCTION/OBJECTIVES

To address the diagnostic delay in axial spondyloarthritis (axSpA), we have cross-culturally adapted the Hamilton axSpA questionnaire, a self-administered screening questionnaire, in the Singapore population. In this study, we compared the performance of various scoring methods for this questionnaire in detecting axSpA.

METHOD

The questionnaire was self-administered by eligible subjects. Scoring methods included method A, the original questionnaire scoring, and methods B-E, scoring developed based on the Assessment of SpondyloArthritis International Society (ASAS) criteria for inflammatory back pain (IBP) and the referral, classification and both referral and classification of axSpA, respectively. The reference standard was diagnosis by a rheumatologist. Since the ASAS criteria-based scoring methods were mainly based on clinical axSpA features, self-report and rheumatologist-assessment of clinical axSpA features were also compared in subjects with axSpA.

RESULTS

Of 1418 subjects (age: 54 ± 14 years, female: 73%) recruited, 46 were diagnosed with axSpA by a rheumatologist. Sensitivities of methods A-E were 35%, 61%, 63%, 48% and 83%, respectively. Self-report of clinical axSpA features exceeded rheumatologist-assessment for arthritis (83 vs 26%), good response to NSAIDs (37 vs 30%), enthesitis (35 vs 30%), dactylitis (20 vs 2%) and family history for axSpA (13 vs 4%). The reverse was true for IBP (41 vs 63%) and uveitis (4 vs 15%).

CONCLUSIONS

A self-administered questionnaire using the ASAS referral and classification criteria-based scoring yielded relatively high sensitivity in detecting axSpA in subjects newly referred to rheumatology clinics. This supports its evaluation as a screening and referral tool in the general population in future studies. Key Points • A self-administered questionnaire could be used as a screening and referral tool. • ASAS referral and classification criteria-based scoring yielded relatively high sensitivity. • Inaccurate perception of clinical axSpA features was observed in axSpA patients.

Treatment of Connective Tissue Disease-Related Intractable Disease with Biological Therapeutics

The treatment of connective tissue disease (CTD) and CTD-related intractable diseases (CTD-IDs) currently depends on the use of steroid therapy. Approximately 20 years have passed since the approval of infliximab for rheumatoid arthritis in 2003. Since then, several biological therapeutics have been marketed and adapted for many CTDs and CTD-IDs other than rheumatoid arthritis. Although conventional treatment for patients with these diseases is rarely used because of their poor prognosis, these cases may benefit from biological therapeutics. However, choosing biological therapeutics is difficult because they have different target molecules compared with conventional therapeutics. In this review, we address the current situation of biological therapeutics for CTD-IDs including Behcet's disease, psoriatic arthritis, ankylosing spondylitis, anti-neutrophil cytoplasmic antibody-related arthritis, and adult Still's disease, as well as the choice of biological therapeutics in clinical practice.

Educational needs and challenges in axial spondyloarthritis

PURPOSE OF REVIEW

Axial spondyloarthritis (axSpA) affects 0.5-1% of the population in many regions of the world. This review summarizes the challenges in medical education around axSpA with attention to evidence around delayed diagnosis, clinician familiarity with typical axSpA features, such as inflammatory back pain and adherence to accepted management principles.

RECENT FINDINGS

Clinicians who commonly manage patients with chronic back pain or other typical axSpA features are not consistently aware of the concept of inflammatory back pain and common extra-spinal manifestations. Further, clinicians may not be familiar with the nonradiographic spectrum of axSpA. Management of patients with possible axSpA does not consistently follow principles that would establish an axSpA diagnosis, and diagnosis of axSpA remains delayed by 6-7 years on average, with evidence suggesting management disparities on the basis of sex and race in some cases. Referral recommendations have increased the probability of axSpA diagnosis up to about 40% and, may complement educational efforts in axSpA.

SUMMARY

Educational efforts in axSpA should focus on providing front-line clinicians with a better understanding of inflammatory back pain, the nonradiographic form of axSpA, and accepted principles in axSpA management.

Axial Psoriatic Disease: Clinical and Imaging Assessment of an Underdiagnosed Condition

The frequent involvement of the spine and sacroiliac joint has justified the classification of psoriatic arthritis (PsA) in the Spondyloarthritis group. Even if different classification criteria have been developed for PsA and Spondyloarthritis over the years, a well-defined distinction is still difficult. Although the majority of PsA patients present peripheral involvement, the axial involvement needs to be taken into account when considering disease management. Depending on the definition used, the prevalence of axial disease may vary from 25 to 70% in patients affected by PsA. To date, no consensus definition has been reached in the literature and the definition of axial involvement in PsA has varied from isolated sacroiliitis to criteria used in ankylosing spondylitis. This article reviews the unmet needs in the clinical and radiological assessment of axial PsA, reporting the various interpretations of axial involvement, which have changed over the years. Focusing on both imaging and clinical standpoints, we reported the prevalence of clinical and radiologic features, describing the characteristics of axial disease detectable by X-rays, magnetic resonance imaging, and PET-CT, and also describing the axial symptoms and outcome measures in patients affected by axial disease.

Axial involvement in psoriatic arthritis: An update for rheumatologists

Psoriatic arthritis (PsA) is a heterogenous, chronic, inflammatory musculoskeletal disease that can lead to peripheral and axial damage and loss of function. Axial involvement occurs in 25% to 70% of patients with PsA, varying greatly depending on its definition, with the key manifestations being sacroiliitis and/or spondylitis. However, there are no agreed-upon classification or diagnostic criteria for axial involvement in PsA and no consensus on treatment paradigms, which complicates management of PsA. There have only been a few studies assessing biologics in patients with PsA with axial involvement, and most treatment plans are based on evidence from patients with axial spondyloarthritis. Rheumatologists therefore face many challenges in the management of axial PsA, including diagnosis, differential diagnosis, and choice of appropriate treatment. In this review, we summarize the clinical presentation, imaging characteristics, differential diagnoses, treatment options, and prognosis of axial PsA, with the aim of increasing rheumatologists' knowledge of this phenotype of PsA and thereby aiding its optimal management.

Ankylosing spondylitis risk factors: a systematic literature review

Radiographic axial spondyloarthritis (also known as ankylosing spondylitis [AS]) is a chronic immune-mediated arthritis characterized by inflammation of the axial skeleton, peripheral joints, and entheses. It is estimated that 1 in every 200 people are affected by AS, making it an important healthcare and socioeconomic issue. In this review, we aim to explore the current understanding of AS risk factors and provide a comprehensive update. Multiple search strings were used to identify articles of interest published in PubMed between January 1, 2013, and February 1, 2021. On the basis of the literature review and analysis, we present up-to-date information on the risk factors of developing AS and our viewpoints on disease onset and progression. Multiple genetic and nongenetic risk factors have been suggested in the onset of AS. HLA-B27 is known to have a strong association with the disease, but other genes have been implicated in disease development. Aside from genetics, other factors are thought to be involved; up to 70% of patients with AS have subclinical intestinal inflammation, suggesting that the origin of the disease may be in the gut. The exact mechanism by which AS onset begins is most likely complex and multifactorial. Key Points • It remains unclear how interactions between genes, microbes, mechanical stress, gender, and other environmental and lifestyle factors predispose patients to the development of ankylosing spondylitis (AS). • The exact mechanisms of AS are complex and multifactorial which will require much future research • Recognizing the risk factors, as well as understanding gene-environment interactions, may offer valuable insights into the etiology of AS and have important implications for diagnosis and treatment strategies.

The IBIS-Q [IBd Identification of Spondyloarthritis Questionnaire]: A Novel Tool to Detect Both Axial and Peripheral Arthritis in Inflammatory Bowel Disease Patients

BACKGROUND AND AIMS

Both peripheral and axial spondyloarthritis [SpA] occur in inflammatory bowel disease [IBD] and represent the commonest extra-intestinal manifestation. We aimed to develop an easy and quick questionnaire through psychometric analysis, to identify peripheral and axial SpA in IBD patients within an integrated combined multidisciplinary rheumatological-gastroenterology clinic.

METHODS

Initially, SpA-IBD experts generated a 42-item list covering SpA manifestations including spinal, articular, and entheseal involvement. The new questionnaire was administered before routine clinical IBD assessment. On the same day, rheumatological assessment, blinded to both history and questionnaire results, was performed to explore the presence of the Assessment of SpondyloArthritis International Society [ASAS] criteria for SpA, diagnostic criteria for fibromyalgia [FM], and non-specific low back pain [NSLB]. Factorial analysis of questionnaire items to identify the main factors-receiver operating characteristic [ROC] curves for sensitivity/specificity and Youden index for cut-off-were performed.

RESULTS

Of the 181 consecutive patients, 56 met the ASAS SpA criteria [prevalence of 30%] with 10 new cases detected [5.5%: seven peripheral and three axial]. Through the psychometric and factorial analysis, we selected 14 items for the final questionnaire [named IBIS-Q]. The IBIS-Q was quick and performed well for detection of axial SpA and peripheral SpA (area under the curve [AUC] 0.88 with 95% confidence interval [CI] 0.830.93). A cut-off of three positive questions had a sensitivity 93% and specificity 77% for SpA patient identification.

CONCLUSIONS

The IBIS-Q is a useful and simple tool to use in IBD clinics for SpA detection, with a good statistical performance. Further studies are needed to validate it.

Evaluating Inflammatory Versus Mechanical Back Pain in Individuals with Psoriatic Arthritis: A Review of the Literature

Psoriatic arthritis (PsA) is a chronic immune-mediated disease characterized by psoriatic skin and nail changes, peripheral joint inflammation, enthesitis, dactylitis, and/or axial involvement, either alone or in combination with each other. The presence of axial involvement has been shown to be a marker of PsA severity; however, there is no widely accepted definition of axial involvement in PsA (axPsA) or consensus on how or when to screen and treat patients with suspected axPsA. Chronic back pain is a prominent feature of axPsA and is thought to have a relevant role in early identification of disease. Chronic back pain can be caused by inflammatory back pain (IBP) or mechanical back pain (MBP). However, MBP can complicate recognition of IBP and delay diagnosis of axPsA. While MBP can also be associated with chronic back pain of ≥ 3 months in duration that is typical of IBP, IBP is characterized by inflammation of the sacroiliac joint and lower spine that is differentiated from MBP by key characteristic features, including insidious onset at age < 40 years, improvement with exercise but not with rest, and nighttime pain. This review discusses the differences in identification and management of IBP and MBP in patients with PsA with axPsA. The summary of available evidence highlights the importance of appropriate and timely screening, difficulties and limitations of differential diagnoses and treatment, and unmet needs in axPsA.

Prevalence of inflammatory back pain and radiographic axial spondyloarthritis in a semi-urban community of Lahore, Pakistan

AIMS

To determine the prevalence of inflammatory back pain (IBP) and radiographic axial spondyloarthritis (SpA) in a semi-urban community of Lahore, Pakistan.

METHODS

This cross-sectional household survey was designed as per the Community Oriented Program for the Control of Rheumatic Diseases (COPCORD) model. In Phase 1, the subjects were interviewed for musculoskeletal (MSK) pain in the last 7 days by clinical assistants. In Phase 2, physiotherapists identified subjects with spinal/back pain and interviewed for Assessment in Spondyloarthritis International Working Group (ASAS) criteria for IBP. In Phase 3 subjects having IBP or chronic back pain (CBP) with an age at onset ≤45 years, were assessed and further investigated.

RESULTS

A total of 4922 subjects with a mean age of 35.3 ± 14.5 years, including 2770 (56%) women were surveyed in Phase 1. MSK pain in last 7 days was reported by 1407 (28.6%) of whom 1034 (21%) had spinal pain. The ASAS criteria for IBP were met in 329 (6.7%, 95% CI 6.0-7.0). In Phase 3, 222 with IBP and 83 having CBP with age at onset ≤45 years were evaluated. Out of this total of 305, 144 (2.9%) were confirmed to have IBP by rheumatologists as per at least 1 of the 3 criteria. ASAS criteria were met in 107 (2.2%, 95% CI 1.8-2.6). ASAS criteria for radiographic axial SpA were met in 47 (1%, 95% CI 0.7-1.3) of the surveyed population.

CONCLUSION

Inflammatory back pain was reported in 6.7% by physiotherapists, confirmed in 3% by rheumatologists. The prevalence of radiographic axial SpA was 1%.

Recognizing Axial Spondyloarthritis: A Guide for Primary Care

Axial spondyloarthritis (axSpA) is an important cause of chronic low back pain and affects approximately 1% of the US population. The back pain associated with axSpA has a characteristic pattern referred to as inflammatory back pain (IBP). Features of IBP include insidious onset before age 45 years, association with morning stiffness, improvement with exercise but not rest, alternating buttock pain, and good response to treatment with nonsteroidal anti-inflammatory drugs. In patients with IBP, it is essential to look for other features associated with spondyloarthritis (SpA), such as enthesitis, dactylitis, peripheral arthritis, extra-articular manifestations (eg, psoriasis, uveitis, or inflammatory bowel disease), human leukocyte antigen B27 positivity, and a family history of SpA. Axial SpA is underrecognized, and a delay of several years between symptom onset and diagnosis is common. However, with new and effective therapies available for the treatment of active axSpA, early recognition and diagnosis are of critical importance. For this narrative review, we conducted a literature search of English-language articles using PubMed. Individual searches were performed to identify potential articles of interest related to axSpA (search terms: ["axSpA" OR "axial SpA" OR "axial spondyloarthritis" OR "ankylosing spondylitis"]) in combination with terms related to IBP ("inflammatory back pain" OR "IBP" OR "chronic back pain" OR "CBP" OR "lower back pain" OR "LBP"), diagnosis (["diagn∗" OR "classification"] AND ["criteria" OR "recommend∗" OR "guidelines"]), and referral ("refer∗"). No date range was formally selected, as we were interested in providing an overview of the evolution of these concepts in clinical practice. We supplemented the review with insights based on our clinical expertise. Patients with chronic back pain should be screened for IBP and other SpA features; suspicion for axSpA should trigger referral to a rheumatologist for further evaluation.

Understanding Barriers in the Pathway to Diagnosis of Ankylosing Spondylitis: Results From a US Survey of 1690 Physicians From 10 Specialties

Objective

Early diagnosis of ankylosing spondylitis (AS) remains challenging because of the high prevalence of chronic back pain in patients initially treated by nonrheumatology health care providers (HCPs). We assessed the patient pathway to rheumatology referral, including HCP recognition of inflammatory back pain (IBP) and other features suggestive of AS, diagnostic workup, treatment, and referral to a specialist with the goal of identifying barriers to patient referral to a rheumatologist.

Methods

US HCPs from 10 specialties were invited to participate in a cross‐sectional web‐based survey on clinical characteristics and diagnostic measures leading to IBP suspicion and the subsequent referral process. Eligible HCPs were actively practicing and had referred a patient with suspected IBP or ocular findings (ophthalmology only) within 12 months. Data were analyzed descriptively.

Results

Of 1690 HCPs, 61% identified morning stiffness lasting more than 30 minutes, 29% sleep disturbance due to back pain, and 28% pain that improves with activity as features suggestive of IBP. Nearly two‐thirds of primary care HCPs reported that they were the first HCPs consulted by patients with suspected IBP. Among HCPs ordering diagnostic blood work, approximately 90% selected antinuclear antibody and rheumatoid factor, whereas 76% selected human leukocyte antigen B27. Almost 40% would treat patients with suspected IBP themselves. HCPs cited lack of adequate specialists nearby (35.1%), insurance restrictions (47.1%), and long wait time (77.0%) as barriers to early referral.

Conclusion

Most HCPs had difficulty identifying features suggestive of IBP and indicated insurance restrictions and long wait times as barriers to early referral of patients with potential AS.

Axial spondyloarthritis 10 years on: still looking for the lost tribe

Despite the publication of various recommendations, quality standards and referral strategies to promote early diagnosis in axial SpA (axSpA) over the last decade, there remains a significant delay to diagnosis, leading to a lost tribe of undiagnosed, untreated patients with persistent back pain and axSpA symptoms. This review discusses the various factors contributing to diagnostic delay in axSpA, while providing recommendations to improve the diagnostic pathway, for example use of the online Spondyloarthritis Diagnosis Evaluation (SPADE) tool (http://www.spadetool.co.uk/). Significant shortcomings exist at both the primary and secondary care level, with healthcare professionals often lacking knowledge and awareness of axSpA. Myths regarding the classical signs and symptoms still prevail, including the perception of axSpA as a male disease, only occurring in individuals who are HLA-B27 positive with raised inflammatory markers. Individuals within this lost tribe of undiagnosed patients are likely lacking adequate treatment and are thereby at risk of worse clinical outcomes. It is therefore vital that public health initiatives are implemented to improve education of healthcare professionals and to ensure early specialist referral, to ultimately improve the lives of patients with axSpA.

Early recognition of patients with axial spondyloarthritis—evaluation of referral strategies in primary care

Objective

Chronic inflammatory back pain (IBP) is frequently reported in axial SpA (axSpA) but also in the general population. We evaluated a recently proposed two-step referral system for early recognition of axSpA in primary care and compare it with other combinations of symptoms and SpA-related items.

Methods

Consecutive chronic back pain patients ≤45 years of age answered a questionnaire and were seen by a primary care physician who decided whether HLA-B27 needed to be determined. They were then referred to a rheumatologist who made the diagnosis. Generally sticking to the two-step system with HLA-B27 as an additional option, combinations with a sensitivity ≥90% and a likelihood ratio &gt;4 were compared.

Results

A total of 326 patients were included, 46 of whom were diagnosed with axSpA (14.1%). The sensitivity of the strategy was 87%, the specificity was 56.8% and the positive and negative predictive values were 24.8% and 96.4%, respectively. A ‘good response to NSAIDs’, ‘morning stiffness &gt;30 min’ and ‘elevated C-reactive protein’ performed best, with a sensitivity of 91%, specificity of 67%, positive predictive value of 31% and negative predictive value of 98%. On that basis, only three patients had to be seen by a rheumatologist to diagnose one.

Conclusion

The earlier proposed referral system worked well but was outperformed by other combinations with high sensitivity and better specificity, which deserve to be prospectively studied.

[Identification of patients with axial spondylarthritis in primary care (AWARE study)]

BACKGROUND

Early detection of patients with axial spondylarthritis (axSpA) in primary care is difficult. The combination of various parameters indicative of inflammatory back pain (AWARE criteria) was found to be beneficial in an initial study.

OBJECTIVE

Review of the criteria for the identification of young patients with axSpA and chronic back pain (≥3 months of back pain).

MATERIAL AND METHODS

In adult patients with chronic back pain and age at onset of symptoms <45 years, orthopedic surgeons documented various possible axSpA characteristics before referral to the rheumatologist.

RESULTS

Overall, the data from 1306 patients were recorded. Of these, ultimately 500 patients were also seen by rheumatologists, 199 patients (39.8%) were diagnosed with axSpA while 301 (60.2%) had non-specific back pain. A total of 87 patients had ankylosing spondylitis (44%) and 112 non-radiographic axSpA (56%). The ASAS classification criteria were fulfilled by 226 patients (45.2%). The mean age of axSpA patients was 38 years, 56% were male with a mean duration of back pain of 98 months. The AWARE criteria had a sensitivity and specificity of 69.3% and 40.3% (n = 343), respectively, when ≥4/5 criteria were chosen. Positive imaging for sacroiliitis using magnetic resonance imaging (MRI) or X‑ray was present in 77% of patients and positive HLA-B27 was identified in 59% of axSpA patients. The combination of positive imaging and HLA-B27 had the highest likelihood ratio for diagnosis of axSpA.

CONCLUSION

Although the study design used here led to a preselection and thus to a bias in the statistical evaluation, the study confirmed the benefit of the AWARE criteria for the early detection of patients with axSpA. In further studies, the 2‑stage approach with initially 3 clinical questions and then an optional HLA-B27 test is currently being investigated further.

Klippel-Feil syndrome misdiagnosed as spondyloarthropathy: case-based review

Spondyloarthropathy refers to any joint disease of the vertebral column, but the term is mainly used for a specific group of disorders called seronegative spondyloarthropathies (SpAs). The axial skeletal involvement, peripheral and extra-articular manifestations and an association with the major histocompatibility complex class I human leukocyte antigen-B27 (HLA B27) are commonly shared features of SpAs. Klippel-Feil syndrome (KFS) is a rare congenital disorder characterized by the fusion of one or more cervical vertebrae, accompanied by various skeletal and extra-skeletal anomalies. We report a case of an adult male patient with HLA B27 positivity presenting with chronic cervical spine pain accompanied by morning stiffness and periodic night pain, with radiologically confirmed ankylosis and fusion of several cervical segments. His medical history included urogenital abnormalities operated in childhood and mild mitral prolapse. Initially suspected diagnosis of an early axial form of SpA was rejected after thorough workup. Instead, the nature of vertebral defects along with the past medical history of urogenital and cardiac abnormalities pointed towards the diagnosis of KFS. HLA B27 presence can be a confounder in patients presenting with spinal pain and that is why the differential diagnosis of CSD-s and SpA can be challenging in some patients.

Use of machine learning techniques in the development and refinement of a predictive model for early diagnosis of ankylosing spondylitis

OBJECTIVE

To develop a predictive mathematical model for the early identification of ankylosing spondylitis (AS) based on the medical and pharmacy claims history of patients with and without AS.

METHODS

This retrospective study used claims data from Truven databases from January 2006 to September 2015 (Segment 1) and October 2015 to February 2018 (Segment 2). Machine learning identified features differentiating patients with AS from matched controls; selected features were used as inputs in developing Model A/B to identify patients likely to have AS. Model A/B was trained and developed in Segment 1, and patients predicted to have AS in Segment 1 were followed up in Segment 2 to evaluate the predictive capability of Model A/B.

RESULTS

Of 228,471 patients in Segment 1 without any history of AS, Model A/B predicted 1923 patients to have AS. Ultimately, 1242 patients received an AS diagnosis in Segment 2; 120 of these were correctly predicted by Model A/B, yielding a positive predictive value (PPV) of 6.24%. The diagnostic accuracy of Model A/B compared favorably with that of a clinical model (PPV, 1.29%) that predicted AS based on spondyloarthritis features described in the Assessment of SpondyloArthritis international Society classification criteria. A simplified linear regression model created to test the operability of Model A/B yielded a lower PPV (2.55%).

CONCLUSIONS

Model A/B performed better than a clinically based model in predicting a diagnosis of AS among patients in a large claims database; its use may contribute to early recognition of AS and a timely diagnosis.

Nonradiographic axial spondyloarthritis

Non-radiographic axial spondyloarthritis (nr-axSpA) is a complex disease process that is part of the spectrum of axial spondyloarthritis (axSpA). This article reviews the current state of the literature as the understanding of this disease spectrum expands. The conceptual history and terminology, genetics, and epidemiology are reviewed. The clinical manifestations, diagnostic approach, and measures of disease activity are examined. Finally the current treatment modalities and recommendations and the research agenda for nr-axSpA are reviewed. With the advent of new criteria, the disease spectrum can be studied in a systematic manner. These data have enriched our knowledge that reflects an earlier or milder form of disease on a spectrum same as that of ankylosing spondylitis (or radiographic axSpA). We learned how patients present in this stage and that despite an unacceptable delay in diagnosis (regardless of the stage), the burden of disease is high and unremitting. nr-axSpA clinical trials have been somewhat heterogeneous (with variable inclusion criteria) but have nevertheless shown considerable efficacy with tumor necrosis factor inhibitors and flare on withdrawal of therapy.

Sacroiliitis - early diagnosis is key

Sacroiliitis, inflammation of the sacroiliac joint (SIJ), may be associated with many rheumatic and nonrheumatic disorders. The diagnosis of sacroiliitis may be difficult in many patients, and awareness of its typical manifestations along with recognition of its diverse presentations and cognizance of the limitations of today’s imaging modalities are critical to good clinical practice. This review presents the didactic approach to the early diagnosis of sacroiliitis in patients with suspected axial spondyloarthritis and other nosologic entities, discussing also differential interpretation of information acquired from patients’ histories, physical examination, and imaging.

Knowledge of features of inflammatory back pain in primary care in the West Midlands: a cross-sectional survey in the United Kingdom

KEY MESSAGES

There is a relative lack of confidence among GPs in the assessment and management of IBP vs. mechanical back pain. A simple screening tool for SpA, applicable in primary care urgently needs to be developed. It is reasonable for patients with symptoms suggestive of inflammatory back pain to be referred to secondary care without further investigations. The objective of this study was to assess current practice of our local general practitioners (GPs) in using clinical features, as well as radiological and laboratory investigations to assess patients with IBP. An online, observational questionnaire-based survey was done in 10 West Midlands CCGs including disparate geographical and socioeconomic areas. The survey consisted of 23 questions based on Calin, Berlin and ESSG Criteria for spondyloarthropathies. GPs were asked to rate the importance of a range of symptoms as indications of IBP IBP (10 point scale, range 1-10), and what their views were on which were the most important treatments for patients with suspected inflammatory back pain(4 point scale, range 1-4). The 4 most important symptoms for predicting inflammatory back pain according to our local cohort of GPs were 'morning stiffness' 'sleep disturbances caused by back pain' 'insidious onset' and 'age of onset' < 45. Among the treatment options, NSAIDs were ranked as the most important treatment option for IBP. DMARDS were rated as the next most important treatment option, ahead of physiotherapy and anti-TNF therapy. This study has highlighted relative lack of confidence among GPs in the assessment of IBP. Whether this reflects a need for education or poor performance of these questions in primary care populations requires further study.

The clinical utility of human leucocyte antigen B27 in axial spondyloarthritis

The association between HLA-B27 and AS was first established in the early 1970s. Since then, our understanding of this disease has changed, such that we now recognize AS to be the extreme of the clinical phenotype within a disease spectrum known as axial SpA (axSpA). Recent advances in therapeutic options have driven the need for earlier diagnosis and many screening strategies have been proposed to facilitate this. In parallel, our understanding of axSpA genetics, and especially the contribution of HLA-B27, has expanded. In this article we will present and discuss the evidence supporting the use of HLA-B27 in clinical practice. We will briefly summarize the evolution of the concept of axSpA, the prevalence of HLA-B27 and axSpA and the potential role of HLA-B27 in the aetiopathogenesis of axSpA and focus on the utility of HLA-B27 in everyday clinical practice.

Clinical Evolution in Patients With New-Onset Inflammatory Back Pain: A Population-Based Cohort Study

OBJECTIVE

Inflammatory back pain (IBP) is often an early manifestation of spondyloarthritis (SpA), but the prognosis of patients with incident IBP is unknown. This study was undertaken to investigate long-term outcomes in patients with IBP, and predictors of progression to SpA, in a population-based cohort.

METHODS

We conducted a retrospective, longitudinal study using the Rochester Epidemiology Project, a longstanding population-based cohort of residents of Olmsted County, MN. Patients ages 16-35 years with clinical visits for back pain from 1999 to 2003 were identified, and we screened these patients for the presence of new-onset IBP and performed medical record reviews to collect data on clinical, laboratory, and imaging features of SpA. Outcomes in these patients were followed up until July 2016. We used survival analysis for competing risks to examine progression to either SpA, a non-SpA diagnosis, or resolution of back pain. Recursive partitioning was used to identify predictors of progression to SpA.

RESULTS

Among 5,304 patients with back pain, we identified 124 patients with new-onset IBP. After a median follow-up of 13.2 years, IBP had progressed to SpA in 39 patients, 15 patients developed a non-SpA diagnosis, and 58 patients had resolution of IBP. At 10 years, the probability of having SpA was 30%, while the probability of resolution of IBP was 43%. The most important predictors for progression to SpA were uveitis, male sex, and family history of SpA.

CONCLUSION

In a minority of patients, new-onset IBP progresses to SpA, while IBP resolves in many. That IBP often resolves may explain the difference between the prevalence of IBP (3-6%) and the prevalence of SpA (0.4-1.3%).

Anti-CD74 antibodies have no diagnostic value in early axial spondyloarthritis: data from the spondyloarthritis caught early (SPACE) cohort

BACKGROUND

Anti-CD74 IgG antibodies are reported to be elevated in patients with axial spondyloarthritis (axSpA). This study assessed the diagnostic value of anti-CD74 antibodies in patients with early axSpA.

METHODS

Anti-CD74 IgG and IgA antibodies were first measured in an exploratory cohort of patients with radiographic axSpA (138 patients with ankylosing spondyloarthritis (AS)) and 57 healthy controls and then were measured in patients with early axSpA (n = 274) and with non-SpA chronic back pain (CBP) (n = 319), participating in the spondyloarthritis caught early (SPACE) prospective cohort study of patients under 45 years old with early back pain (for ≥ 3 months, but ≤ 2 years).

RESULTS

In the exploratory cohort, anti-CD74 IgG antibodies were present in 79.7% of patients with AS vs. 43.9% of healthy controls (p < 0.001). Anti-CD74 IgA antibodies were present in 28.5% of patients with AS vs. 5.3% of healthy controls (p < 0.001). In the SPACE cohort, anti-CD74 IgG antibody levels were present in 46.4% of the patients with axSpA vs. 47.9% of the patients with CBP (p = 0.71). Anti-CD74 IgA antibodies were present in 54.7% of the patients with axSpA and 37.0% of the patients with CBP (p < 0.001). This resulted in a positive predictive value of 58.8% (compared to a prior probability of 46.2%) and a negative predictive value of 59.1% (compared to a prior probability of 53.8%). In a regression model, total serum IgA was associated with axSpA odds ratio (OR) 1.19, p < 0.001) whereas anti-CD74 IgA was not (OR) 1.01, p = 0.33). Furthermore, anti-CD74 IgA was associated with sacroiliitis on magnetic resonance imaging (MRI) (OR) = 2.50, p = 0.005) and heel enthesitis (OR) = 2.56, p = 0.002).

CONCLUSIONS

Albeit anti-CD74 IgA is elevated in patients with early axSpA, this elevation is not sufficiently specific to yield significant diagnostic value in patients under 45 years old presenting with early back pain.

Evaluation of multiple referral strategies for axial spondyloarthritis in the SPondyloArthritis Caught Early (SPACE) cohort

BACKGROUND

Several models have been proposed to refer patients with possible axial spondyloarthritis (axSpA) to a rheumatologist. Our aim was to evaluate performance of these models in a single cohort.

METHODS

13 referral models found in the literature were evaluated in the Leiden SPondyloArthritis Caught Early (SPACE) cohort, which includes patients with back pain (≥3 months, ≤2 years, onset <45 years; n=261) referred to a rheumatology outpatient clinic. Imaging was not considered as a referral parameter. Performance of the strategies was evaluated (sensitivity, specificity, positive likelihood ratio (LR+)) using diagnosis by a rheumatologist as an external standard. For secondary analyses, fulfilment of the Assessment in SpondyloArthritis international Society (ASAS) axSpA criteria was used as an external standard.

RESULTS

In total, 107/261 patients were diagnosed with axSpA. Most models performed well regarding sensitivity and specificity. The MASTER strategy showed a balanced sensitivity/specificity with the highest LR+. The ASAS and Brandt I strategies are the most sensitive strategies. Using classification by ASAS axSpA criteria as the external standard gave comparable results. Most patients missed by the strategies fulfilled the imaging arm of the ASAS axSpA criteria.

CONCLUSIONS

Most referral models performed well, although patients in SPACE have already been referred, which may have led to overestimation of performance. If no patient is to be missed, the ASAS strategy would be most preferable. If the number of referrals needs to be limited, the MASTER strategy seems to perform best. The 'ideal' referral strategy may be different from country to country, due to differences in healthcare structure and prevalence of referral parameters such as human leucocyte antigen-B27.

Evaluation and Management of the Patient With Suspected Inflammatory Spine Disease

Axial spondyloarthritis (AxSpA) is a chronic inflammatory rheumatic disease characterized by inflammatory back pain (IBP) that manifests in childhood, late adolescence, or early adulthood. Ankylosing spondylitis (AS) and nonradiographic AxSpA represent 2 ends of the AxSpA spectrum. Diagnosis can be challenging because patients develop IBP that may not be associated with radiographic changes in the sacroiliac joints. Patients early in the course of disease are estimated to have at least the same level of disease activity and pain as patients with established disease; thus, they could benefit substantially from earlier diagnosis. Although the recent use of magnetic resonance imaging and its inclusion in diagnostic criteria has enhanced the identification of early AxSpA, improvement in early diagnosis has not been consistently reported across all studies. Limited knowledge of the continuum of AxSpA disease manifestations and lack of recognition of IBP in primary practice may contribute to this. Implementing a referral strategy that identifies patients with IBP for additional testing and assessment may lead to better recognition of early signs and symptoms of AxSpA, thereby offering the potential for improved patient outcomes. This review presents an overview of the epidemiology, clinical characteristics, and burdens of AxSpA, followed by a case presentation outlining approaches to the evaluation and management of a patient with suspected inflammatory spine disease.

[Inflammatory spinal diseases: axial spondyloarthritis : Central importance of imaging]

The diagnosis of axial spondyloarthritis (axSpA) includes classical ankylosing spondylitis (AS) as well as earlier stages and abortive courses of the disease, in which structural alterations have not yet occurred. These are classified as non-radiographic axSpA (nr-axSpa). Inflammatory changes in the entire axial skeleton are characteristic for axSpA and can be visualized by magnetic resonance imaging (MRI), while in most patients structural alterations, such as new bone formation with syndesmophytes and ankylosis develop in the later course of the disease. These bony alterations can best be visualized by conventional radiography and by computed tomography. Certain MRI sequences are nowadays considered as the standard method for depiction of inflammatory changes in axSpA. The introduction of MRI has led to a paradigm shift for this disease because the inflammatory lesions characteristic for the disease can be visualized at an early stage using appropriate MRI sequences.

High Prevalence of Undiagnosed Axial Spondyloarthritis in Patients with Chronic Low Back Pain Consulting Non-Rheumatologist Specialists in Belgium: SUSPECT Study

INTRODUCTION

Diagnosis of axial spondyloarthritis (SpA) can be delayed for several years mainly because of low awareness of axial SpA among non-rheumatologists who are the first interlocutors of potential SpA patients. One strategy to decrease the delay between appearance of first symptoms and diagnosis of axial SpA and to allow early management of the disease is to provide the non-rheumatologists with tools to identify patients requiring prompt referral to rheumatologists. This study was designed to evaluate in a real-world setting whether screening patients with chronic low back pain who consult physical medicine and rehabilitation (PMR) physicians, orthopedists, and ophthalmologists is useful in detecting axial SpA.

METHODS

During this non-interventional cross-sectional study, data from 161 patients with chronic back pain, consulting an orthopedist, PMR physician, or ophthalmologist were collected during a single visit. Any patient who presented with at least four out of five symptoms of inflammatory back pain (IBP) and at least one additional SpA feature were to be referred to a rheumatologist. Analysis was purely descriptive.

RESULTS

IBP was diagnosed in approximately half of the patients (89 patients) and 72 of them met the referral criteria. A total of 117 patients were finally referred to a rheumatologist and axial SpA was diagnosed for 37 of them.

CONCLUSIONS

The high prevalence of undiagnosed axial SpA in patients with chronic back pain visiting PMR physicians, orthopedists, and ophthalmologists suggests that these healthcare professionals may play a key role in the strategy developed to shorten the delay observed in the formal diagnosis of SpA.

FUNDING

Abbvie.

Challenges of diagnosis and management of axial spondyloarthritis in North Africa and the Middle East: An expert consensus

Axial spondyloarthritis (SpA) is a spectrum of inflammatory disease with stages characterized by both nonradiographic and radiographic sacroiliitis. Nonradiographic axial SpA is associated with health-related quality-of-life impairment and may progress to ankylosing spondylitis. Axial SpA has a low prevalence in some countries in North Africa and the Middle East, and pooling of data and resources is needed to increase understanding of the regional picture. Early diagnosis and effective treatment are required to reduce disease burden and prevent progression. Anti-TNF therapy is recommended for patients with persistently high disease activity despite conventional treatment, and has been shown to be effective in patients without radiographic damage. Diagnostic delays can be an obstacle to early treatment and appropriate referral strategies are needed. In some countries, restricted access to magnetic resonance imaging and anti-TNF agents presents a challenge. In this article, a group of experts from North Africa and the Middle East evaluated the diagnosis and management of axial SpA with particular reference to this region.

Sponyloarthritis features forecasting the presence of HLA-B27 or sacroiliitis on magnetic resonance imaging in patients with suspected axial spondyloarthritis: results from a cross-sectional study in the ESPeranza Cohort

Introduction

Chronic back pain (CBP) is frequently the presenting symptom in patients with suspected axial spondyloarthritis (axSpA). Presence of sacroiliitis on magnetic-resonance-imaging (MRI) or HLA-B27 adds to diagnostic certainty. However, these costly tests cannot be applied in all patients with CBP. This study aims to investigate which SpA features increase the likelihood of a positive HLA-B27 or positive MRI of the sacroiliac-joints (MRI-SI) in patients with suspected axSpA.

Methods

Data from 665 patients with CBP within the ESPeranza Programme were analysed. Diagnostic utility measures (LR+, LR−) for a positive MRI-SI or HLA-B27 were calculated for various definitions of inflammatory back pain (IBP), their separate items and for other SpA features.

Results

Pretest probabilityies of a positive result was 41 % for MRI-SI and 40 % for HLA-B27. For a positive MRI-SI result the most useful IBP characteristic was alternating buttock pain (LR + =2.6). Among the IBP-criteria, fulfillment of the ‘ASAS criteria’ (LR + =2.1) was most contributory. Interestingly, the addition of alternating buttock pain to the Calin/ASAS-IBP criteria (LR + =6.0 and 5.5, respectively) or the addition of awakening at second half of night to the Calin-IBP criteria (LR + =5.5) increased the pre-test probability of MRI-sacroiliitis from 41 % to 79–80 %. Dactylitis (LR + =4.1) and inflammatory bowel disease (IBD) (LR + =6.4) increased this probability to 73 % and 81 %, respectively. To forecast HLA-B27 positivity, awakening at the second half of the night, fulfillment of the ASAS-IBP definition and uveitis were the most useful, but only marginally predictive (LR + = 1.3, 1,6 and 2.6, respectively).

Conclusions

If patients with suspected axial SpA have either 1) IBP according to Calin/ASAS definition plus alternating buttock pain, or 2) IBP according to Calin definition plus awakening at night, or 3) dactylitis or 4) IBD, the probability of finding a positive MRI-SI increases significantly.