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

Prevalence of Axial Spondyloarthritis in Young People With Chronic Low Back Pain at a Hospital-Based Health Management Organization: A 10-Year Database Study

INTRODUCTION

There is scarce information on the prevalence of axial spondylarthritis (axSpA) using the Assessment of SpondyloArthritis International Society (ASAS) criteria and even less in Latin America. This study aimed to estimate the prevalence of axSpA by applying the ASAS 2009 criteria to a medical records review study of young people with chronic low back pain (LBP) at a university hospital-based health management organization.

METHODS

Electronic medical records from the Hospital Italiano de Buenos Aires health management organization were reviewed to estimate the prevalence of axSpA (radiographic axSpA [r-axSpA] and nonradiographic axSpA [nr-axSpA]) using the ASAS 2009 axSpA criteria in all patients with chronic LBP (≥3 months) aged <45 years at the first LBP appointment, observed between 2009 and 2019.

RESULTS

Among 795 young people with CLBP, the estimated prevalence of axSpA was 5.78% (r-axSpA, 2.76%; nr-axSpA, 3.02%). Ten of 46 patients (21.74%) with axSpA (all nr-axSpA) were undiagnosed, with an undiagnosed axSpA prevalence of 1.26%. The median interval between the first LBP appointment and diagnosis was 34.6 months for axSpA (58.7 vs. 23.1 months for r-axSpA vs. nr-axSpA). Previously diagnosed r-axSpA and nr-axSpA patients had comparable use of biological disease-modifying antirheumatic drugs (bDMARDs) (45% vs. 36%) and delays between nonsteroidal anti-inflammatory drug failure and bDMARD initiation (median, 2.76 vs. 2.66 months).

CONCLUSION

In our cohort of young persons with chronic LBP, the prevalence of axSpA was approximately 6%, with a high prevalence of undiagnosed axSpA, which could explain the low prevalence of axSpA reported in previous studies in Latin America.

Development of a Physiotherapist-Coordinated Interdisciplinary Rehabilitation Intervention for People with Suspected Axial Spondyloarthritis: The SPINCODE Rehabilitation Intervention

Background: People with early axial spondyloarthritis experience a diagnostic delay and a similar disease burden as people with axial spondyloarthritis at a later stage of the disease. In many European countries, patients with early axial spondyloarthritis do not have access to an interdisciplinary rehabilitation team. The objective of this study was to develop a new evidence-based physiotherapist-coordinated interdisciplinary rehabilitation intervention for individuals suspected of axial spondyloarthritis. This development of the rehabilitation intervention is part of the SPINCODE project which focusses on early diagnosis and treatment for people with axial spondyloarthritis. Methods: The development of the intervention encompasses: (i) identifying the evidence base and program theories; (ii) modeling and remodeling the intervention; and (iii) describing the developed intervention. Results: The six-month SPINCODE rehabilitation intervention is a physiotherapist-coordinated, interdisciplinary, outpatient rehabilitation intervention at a specialized rheumatology hospital. The intervention consists of: (i) individual physiotherapist-coordinated consultations with assessment, goal setting, tailored physical activity support, and the defined goals, and coordination across the interdisciplinary team at the hospital and across primary and secondary healthcare levels; (ii) group sessions, encompassing patient education and peer support; and (iii) optional individual support from the interdisciplinary team. Physiotherapists from private care working with the patient enrolled in the SPINCODE study are offered digital support from the hospital-based physiotherapists. Conclusions: The developed physiotherapist-led interdisciplinary SPINCODE rehabilitation intervention is ready for feasibility testing.

Diagnostic delay in axial spondylarthritis: A lost battle?

Diagnostic delay in axial spondylarthritis (axSpA) remains an unacceptable worldwide problem; with evidence suggesting significant detrimental impact both clinically on the individual, and economically on society. There is therefore, a need for global action across various healthcare professions that come into contact with patients living, and suffering, with undiagnosed axSpA. Recent estimates of the median diagnostic delay suggest that globally, individuals with axSpA wait between 2 and 6 years for a diagnosis - revealing a clear benchmark for improvement. This timespan presents a window of opportunity for earlier diagnosis and intervention, which will likely improve patient outcomes. This review describes the current diagnostic delay as estimated across countries and over time, before presenting evidence from published strategies that may be implemented to improve this delay across primary and secondary care, including for specialties treating extra-musculoskeletal manifestations of axSpA (ophthalmology, gastroenterology, dermatology). Ongoing campaigns tackling delayed diagnosis in axSpA are also highlighted.

Increase in axial spondyloarthritis diagnoses after the introduction of the ASAS criteria: a systematic review

To explore the proportion of axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA) diagnoses within all newly referred patients visiting rheumatology outpatient clinics. And more specifically, to analyze whether there is an effect of the introduction of the ASAS and CASPAR classification criteria for axSpA and PsA. We systematically searched Embase, Medline Ovid, Cochrane Central and Web of Science from database inception to November 2022. Articles that investigated new onsets of axSpA and PsA in adults from rheumatology clinics were included. In total, 170 out of 7139 studies were found eligible for full-text review, after which 33 unique studies were included. Seventeen studies reported new onsets of axSpA, and 20 studies of PsA. The pooled proportion of axSpA within all newly referred patients was 19% (95% CI 15-23%) and 18% (95% CI 14-22%) for PsA. The proportion of axSpA before 2009 was 3% (95% CI 0-6%) and increased up to 21% (95% CI 14-28%) after 2009. For PsA, limited data were available in order to analyze the proportions of PsA before 2006. Overall, heterogeneity was high (I² > 95%, p < 0.001) that was most likely caused by geographical area, study design, setting and use of different referral strategies. The pooled proportion of axSpA and PsA among patients referred to the rheumatology outpatient clinic was 19 and 18%, respectively. Although the proportion of diagnosed axSpA patients seemed to increase after the introduction of the ASAS criteria, due to the large heterogeneity our findings should be interpreted with caution.

Expert recommendations on early diagnosis and referral of axial spondyloarthritis in the Kingdom of Saudi Arabia

Axial spondyloarthritis is a chronic inflammatory disorder that primarily involves the axial skeleton (sacroiliac joints and spine), causing stiffness, severe pain and fatigue. In some patients, definitive structural damage of sacroiliac joints is visible on imaging and is known as radiographic axial spondyloarthritis. Some patients do not have a clear radiographic damage of the sacroiliac joints, and this subtype is known as non-radiographic axial spondyloarthritis. Early diagnosis is important for reducing the risk of irreversible structural damage and disability. Management of axial spondyloarthritis is challenging in Saudi Arabia because of inadequate disease knowledge and the unavailability of local guidelines. Therefore, this expert consensus is intended to provide recommendations, including the referral pathway, the definition of remission and the treat-to-target approach, to all healthcare professionals for the management of patients with axial spondyloarthritis. A Delphi technique of consensus was developed by involving an expert panel of 10 rheumatologists, 1 dermatologist and 1 general physician. The experts offered consensus-based recommendations based on a review of available scientific evidence and clinical experience for the referral, screening and management of patients with axial spondyloarthritis.

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.

The IMPACT study: A clustered randomized controlled trial to assess the effect of a referral algorithm for axial spondyloarthritis

BACKGROUND

A substantial number of patients with chronic low back pain (CLBP) have axial spondyloarthritis (axSpA), but early recognition of these patients is difficult for general practitioners (GPs). The Case Finding Axial Spondyloarthritis (CaFaSpA) referral strategy has shown to be able to identify patients with CLBP at risk for axSpA, but its impact on clinical daily practice is yet unknown.

OBJECTIVE

To assess the effect of the CaFaSpA referral strategy on pain caused by disability in primary care patients with CLBP.

METHODS

Within this clustered randomized controlled trial 93 general practices were randomized to either the CaFaSpA referral model (intervention) or usual primary care (control). In each group primary care patients between 18 and 45 years with CLBP were included. The primary outcome was disability caused by CLBP, measured with the Roland Morris Disability Questionnaire (RMDQ) at baseline and four months. Secondary outcome was the frequency of new axSpA diagnosis. Descriptive analyses were performed, and a linear mixed-effects model was used.

RESULTS

In total 679 CLBP patients were included of which 333 patients were allocated to the intervention group and 346 to the control group. Sixty-four percent were female and mean age was 36.2 years. The mean RMDQ score at baseline was 8.39 in the intervention group and 8.61 in the control group. At four months mean RMDQ score was 7.65 in the intervention group and 8.15 in the control group. This difference was not statistically significant (p = 0.50). Six (8%) out of the 75 finally referred patients, were diagnosed with axSpA by their rheumatologist.

CONCLUSIONS

The CaFaSpA referral strategy for axSpA did not have an effect on disability after four months caused by CLBP. However, the strategy is able to detect the axSpA patient within the large CLBP population sufficiently. Trial registration number: NCT01944163, Clinicaltrials.gov.

Variations in gut microbial profiles in ankylosing spondylitis: disease phenotype-related dysbiosis

Background

Microbial involvement in ankylosing spondylitis (AS) has been suggested; however, the relationship between gut microbiome and the disease phenotypes of AS remains to be established. This study was to characterize and investigate differences in the gut microbiome between AS patients and healthy controls (HCs), and to determine whether the gut microbiome profile associated with the disease phenotypes.

Methods

16S rRNA gene V4 region sequencing was performed on fecal DNA isolated from stool samples collected from 41 patients with AS [20 axial AS (axAS) and 21 peripheral AS (pAS)] and 19 HCs. QIIME based pipeline was used to process the raw sequence data. Alpha and beta diversities were assessed using QIIME, and comparisons of gut microbiome profile were performed using linear discriminant analysis (LDA) effect size (LEfSe) to examine differences between groups and subgroups. A gut microbiota-based model for predictive diagnosis of AS was constructed using random forest algorithm and its predictive value was assessed by receiver-operating characteristic analyses.

Results

Our results showed that fecal microbial communities in patients with AS differ significantly from those in HCs, driven by a higher abundance of 7 genera (Prevotella_9, Dialister, Comamonas, Collinsella, Streptococcus, Alloprevotella and Prevotella_2) and a lower abundance of 4 genera (Eubacterium_ruminantium_group, Ruminococcus_gnavus_group, Lachnospira and Bacteroides). In addition, pAS patients were more enriched in Comamonas, Streptococcus and Collinsella, while axAS patients were more enriched in Prevotella_2. An 8 genera-based model showed high accuracy for distinguishing AS patients from HCs with an area under the curve (AUC) up to 0.950.

Conclusions

Our results revealed specific alterations in the gut microbiome in patients with different phenotypes of AS, and the classification model based on gut microbial features might provide a new direction for future clinical diagnosis. Lastly, discovery of the associated microbes of AS in the gut microbiome may help us to seek more treatments for this disease.

Added Value of Anti-CD74 Autoantibodies in Axial SpondyloArthritis in a Population With Low HLA-B27 Prevalence

Axial spondyloarthritis (axSpA) is often diagnosed late due to the non-specific nature of its main symptom [chronic back pain (CBP)] and to the paucity of diagnostic markers, particularly in regions with low HLA-B27 prevalence, such as the Middle-East. We tested the performance of IgG4 and IgA anti-CD74 antibodies as an early diagnostic marker for axSpA, compared with the performance of HLA-B27, in Lebanon. Sera of axSpA patients diagnosed by the rheumatologist and also fulfilling the imaging arm of the ASAS criteria (patients) and of blood donors (BD) (controls) were analyzed for HLA-B27, IgG4 and IgA anti-CD74, blinded to clinical characteristics. Receiver Operating Characteristic curves were constructed to identify an optimal cut-off point for anti-CD74 antibodies. Diagnostic properties were calculated (sensitivity, specificity, positive, and positive predictive values (PPV, NPV), Likelihood ratios) for each marker. Forty-nine axSpA patients and 102 BD were included in the final analysis. IgA anti-CD74 correlated poorly with axSpA (Area Under the Curve (AUC) 0.657), whereas IgG4 anti-CD74 had a good discriminative value (AUC 0.837). Respectively, for HLA-B27, IgG4 anti-CD74, and the combination of both, we found a sensitivity of 33-92-33%, specificity of 96-79-98%, PPV 80-68-89%, NPV 75-95-75%, and LR+ 8.2-4.4-16.5. IgG4 anti-CD 74 were positive in 88% of HLA-B27 negative axSpA patients, and correlated with BASDAI. In this first study in a population with low HLA-B27 prevalence, IgG4 anti-CD74 antibodies combined with HLA-B27 showed higher diagnostic value than HLA-B27 alone for early axSpA. IgG4 anti-CD74 should be considered for further evaluation as an early axSpA diagnostic marker in future dedicated research, particularly in patients with CBP.