The Spondyloarthritis Research Consortium of Canada Registry for Spondyloarthritis

Spectrum of Spondyloarthritis Among Chinese Populations

Purpose of Review

This review aims to emphasize interesting and important new findings with a focus on the spectrum of spondyloarthritis (SpA) in China.

Recent Findings

Over the past decade, significant advances have been made in the investigation of SpA epidemiology, the exploration of genetic and environmental risk factors, the identification of clinical features, and the updating of treatment protocols in the Chinese population. The prevalence of ankylosing spondylitis (AS) in China is 0.20–0.42%, and the prevalence of HLA-B27 in AS patients is 88.8–89.4%. HLA-B*2704 is the most common subtype in Chinese AS patients, followed by HLA-B*2705. HLA-A*01, more precisely HLA-A*01:01, may be associated with psoriatic arthritis (PsA). Tumor necrosis factor inhibitors and IL-17A inhibitors have been shown to be effective and safe for AS patients in China. Juvenile-onset AS is relatively rare, accounting for only 9.1% of the AS population. The prevalence of arthritis related to inflammatory bowel disease is 6.9 to 7.2%. A Chinese study showed that the most frequently prescribed medication was methotrexate (66.4%). Biological agents were prescribed in only16.4% of patients with PsA.

Summary

This review summarizes the latest research in the epidemiology, pathogenesis, clinical manifestations, and management of SpA among Chinese populations. Multiple HLA associations with SpA have also been described, and it is hoped that discoveries of such ethnic-specific risk factor(s) and understanding of their pathological mechanisms may potentially lead to newer targeted therapies for the Chinese populations worldwide.

Comparison of Clinical Features in HLA-B27 Positive and Negative Patients With Axial Spondyloarthritis: Results From a Cohort of 4,131 Patients

Objective: The aim of our study was to assess the influence of the HLA-B27 status on axial spondyloarthritis (axSpA) in the largest cohort in China.

Methods: An observational, cross-sectional, and analytic study of axSpA patients from the China axSpA database was performed. Demographic and clinical data were compared in terms of the HLA-B27 status. Univariate and multivariate analyses were performed to identify variables related to HLA-B27 presence.

Results: We enrolled 4,131 patients in this study; of those, 36,95 (89.4%) were HLA-B27 positive. In the multivariate analysis, male gender (p < 0.001), younger age (p < 0.001), a disease duration of more than 3 years (p < 0.001), a family history of SpA (p < 0.001), uveitis (p < 0.001), ASDAS-CRP (p < 0.001), and biologic treatment (p < 0.001) were the main variables that were independently related to HLA-B27 presence, whereas a diagnosis delay time >36 months (p < 0.001) and psoriasis (p < 0.001) were independently related to HLA-B27 absence.

Conclusion: In Chinese axial SpA patients, presence of HLA-B27 is associated with the male sex, younger age, longer disease duration, greater family aggregation, and higher frequency of uveitis; absence of HLA-B27 is associated with longer diagnosis delay time and higher frequency of psoriasis.

Prevalence and impact of comorbidities in axial spondyloarthritis: systematic review and meta-analysis

OBJECTIVES

Comorbidities are common in people with axial spondyloarthritis (axSpA). In this systematic review and meta-analysis, we aimed to: (i) describe the prevalence of commonly reported comorbidities, (ii) compare comorbidities between axSpA and control populations, and (iii) examine the impact of comorbidity burden on axSpA outcomes.

METHODS

We systematically searched Medline, PubMed, Scopus and Web of Science using a predefined protocol in accordance with Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. We excluded studies of only one comorbid condition or a few closely related diseases within one organ system. Where possible, meta-analysis was performed using random-effects models.

RESULTS

A total of 40 studies were included for analysis. 36 studies reported prevalence of comorbidities, amounting to a combined sample size of 119 427 patients. The number of comorbidities studied ranged from 3 to 43. The most prevalent individual comorbidities were hypertension (pooled prevalence 23%), hyperlipidaemia (17%) and obesity (14%). Eleven studies consistently showed higher prevalence of comorbidities in axSpA than controls, particularly large differences were seen for depression [pooled odds ratio (OR) 1.80] and heart failure (OR 1.84). Comorbidities (total number of and individual conditions) were also associated with axSpA disease activity, functional impairment, quality of life, work productivity and mortality.

CONCLUSIONS

Comorbidities are common in axSpA, particularly cardiovascular diseases and risk factors. Most comorbidities were more prevalent in axSpA patients than in control populations. Overall comorbidity burden, and many individual conditions, were associated with axSpA outcomes including worse disease severity, work productivity and mortality.

Does evaluation of the ligamentous compartment enhance diagnostic utility of sacroiliac joint MRI in axial spondyloarthritis?

Introduction

Inflammation of the sacroiliac joints (SIJ) is a fundamental clinical feature of axial spondyloarthritis (SpA). The anatomy of the irregularly shaped SIJ is complex with an antero-inferior cartilaginous compartment containing central hyaline and peripheral fibrocartilage, and a dorso-superior ligamentous compartment. Several scoring modules to systematically assess SIJ magnetic resonance imaging (MRI) in SpA have been developed. Nearly all of them are based on the cartilaginous joint compartment alone. However, there are only limited data about the frequency of inflammatory lesions in the ligamentous compartment and their potential diagnostic utility in axial SpA. We therefore aimed to evaluate the ligamentous compartment on sacroiliac joint MRI for lesion distribution and potential incremental value towards diagnosis of SpA over and above the traditional assessment of the cartilaginous compartment alone.

Methods

Two independent cohorts of 69 and 88 consecutive back pain patients ≤50 years were referred for suspected SpA (cohort A) or acute anterior uveitis plus back pain (cohort B). Patients were classified according to rheumatologist expert opinion based on clinical, radiographic and laboratory examination as having nonradiographic axial SpA (nr-axSpA; n = 51), ankylosing spondylitis (n = 34), or nonspecific back pain (NSBP; n = 72). Five blinded readers assessed SIJ MRI globally for presence/absence of SpA. Bone marrow edema (BME) and fat metaplasia were recorded in the cartilaginous and ligamentous compartment. The incremental value of evaluating the ligamentous additionally to the cartilaginous compartment alone for diagnosis of SpA was graded qualitatively. We determined the lesion distribution between the two compartments, and the impact of the ligamentous compartment evaluation on diagnostic utility.

Results

MRI bone marrow lesions solely in the ligamentous compartment in the absence of lesions in the cartilaginous compartment were reported in just 0–2.0/0–4.0 % (BME/fat metaplasia) of all subjects. Additional assessment of the ligamentous compartment was regarded as essential for diagnosis in 0 and 0.6 %, and as contributory in 28.0 and 7.7 % of nr-axSpA patients in cohorts A and B, respectively. Concomitant BME in both compartments was evident in 11.6–42.0 % of nr-axSpA and 2.1–2.4 % of NSBP patients.

Conclusion

Assessing the ligamentous compartment on SIJ MRI provided no incremental value for diagnosis of axial SpA. However, concomitant BME in both compartments may help discriminate nr-axSpA from NSBP.

Development and preliminary validation of the spondyloarthritis research consortium of Canada magnetic resonance imaging sacroiliac joint structural score

OBJECTIVE

There is an unmet need for reliable assessment of structural progression in the sacroiliac joints (SIJ) of patients with spondyloarthritis (SpA), but radiography is unreliable and lacks responsiveness. We aimed to develop and validate a new scoring method for structural lesions based on magnetic resonance imaging (MRI), the Spondyloarthritis Research Consortium of Canada (SPARCC) SIJ Structural Score (SSS).

METHODS

The SSS method for assessment of structural lesions is based on T1-weighted spin echo MRI, validated lesion definitions, slice selection according to well-defined anatomical principles, and dichotomous scoring (lesion present/absent) of 5 consecutive slices through the cartilaginous portion of the joint. Scoring ranges are fat metaplasia (0-40), erosion (0-40), backfill (0-20), and ankylosis (0-20). We progressively conducted 3 validation exercises with 2-4 readers on baseline, and either 2-year (exercises 1 and 2) or 1-year (exercise 3) scans from 147 patients with SpA assessed blinded to timepoint. Interobserver reliability was assessed by intraclass correlation coefficient (ICC) and smallest detectable change (SDC).

RESULTS

Interobserver reliability for status score was good to excellent for ankylosis (ICC 0.79-0.98), consistently good for fat metaplasia (ICC 0.71-0.78), moderate to good for erosion (ICC 0.58-0.62), and fair to good for backfill (ICC 0.35-0.66). Reliability for change scores was moderate to good for all structural lesions despite the relatively small changes in scores, and was highest for fat metaplasia when both ICC and SDC values were compared.

CONCLUSION

The new SPARCC MRI SSS method can detect structural changes in the SIJ with acceptable reliability over a 1-2-year timeframe, and should be further validated in patients with SpA.

Tumor necrosis factor inhibitor therapy but not standard therapy is associated with resolution of erosion in the sacroiliac joints of patients with axial spondyloarthritis

Introduction

Radiography is an unreliable and insensitive tool for the assessment of structural lesions in the sacroiliac joints (SIJ). Magnetic resonance imaging (MRI) detects a wider spectrum of structural lesions but has undergone minimal validation in prospective studies. The Spondyloarthritis Research Consortium of Canada (SPARCC) MRI Sacroiliac Joint (SIJ) Structural Score (SSS) assesses a spectrum of structural lesions (erosion, fat metaplasia, backfill, ankylosis) and its potential to discriminate between therapies requires evaluation.

Methods

The SSS score assesses five consecutive coronal slices through the cartilaginous portion of the joint on T1-weighted sequences starting from the transitional slice between cartilaginous and ligamentous portions of the joint. Lesions are scored dichotomously (present/absent) in SIJ quadrants (fat metaplasia, erosion) or halves (backfill, ankylosis). Two readers independently scored 147 pairs (baseline, 2 years) of scans from a prospective cohort of patients with SpA who received either standard (n = 69) or tumor necrosis factor alpha (TNFα) inhibitor (n = 78) therapy. Smallest detectable change (SDC) was calculated using analysis of variance (ANOVA), discrimination was assessed using Guyatt’s effect size, and treatment group differences were assessed using t-tests and the Mann–Whitney test. We identified baseline demographic and structural damage variables associated with change in SSS score by univariate analysis and analyzed the effect of treatment by multivariate stepwise regression adjusted for severity of baseline structural damage and demographic variables.

Results

A significant increase in mean SSS score for fat metaplasia (P = 0.017) and decrease in mean SSS score for erosion (P = 0.017) was noted in anti-TNFα treated patients compared to those on standard therapy. Effect size for this change in SSS fat metaplasia and erosion score was moderate (0.5 and 0.6, respectively). Treatment and baseline SSS score for erosion were independently associated with change in SSS erosion score (β = 1.75, P = 0.003 and β = 0.40, P < 0.0001, respectively). Change in ASDAS (β = −0.46, P = 0.006), SPARCC MRI SIJ inflammation (β = −0.077, P = 0.019), and baseline SSS score for fat metaplasia (β = 0.085, P = 0.034) were independently associated with new fat metaplasia.

Conclusion

The SPARCC SSS method for assessment of structural lesions has discriminative capacity in demonstrating significantly greater reduction in erosion and new fat metaplasia in patients receiving anti-TNFα therapy.

Does spinal MRI add incremental diagnostic value to MRI of the sacroiliac joints alone in patients with non-radiographic axial spondyloarthritis?

Objective

To assess the incremental diagnostic value of spine MRI evaluated separately from and combined with sacroiliac joint (SIJ) MRI in non-radiographic axial spondyloarthritis (nr-axSpA) compared with SIJ MRI alone.

Methods

The study sample comprised two independent cohorts A/B of 130 consecutive patients aged ≤50 years with back pain, newly referred to two university clinics, and 20 healthy controls. Patients were classified according to clinical examination and pelvic radiographs as having nr-axSpA (n=50), ankylosing spondylitis (n=33), or non-specific back pain (n=47). Four readers assessed SIJ and spine MRI separately 6 months apart, and 1–12 months later both scans simultaneously using standardised modules. Readers recorded presence/absence of SpA and their level of confidence in this conclusion on a 0–10 scale (0=definitely not; 10=definite). We analysed differences between SIJ MRI versus spine MRI alone, and SIJ MRI alone versus combined MRI, descriptively by the number/percentage of subjects according to the mean of four readers.

Results

In cohorts A/B, 15.8%/24.2% of patients with nr-axSpA having a negative SIJ MRI were reclassified as being positive for SpA by global evaluation of combined scans. However, 26.8%/11.4% of non-specific back pain controls and 17.5% of healthy volunteers with a negative SIJ MRI were falsely reclassified as having SpA by combined MRI. Low confidence in a diagnosis of SpA by SIJ MRI increased to high confidence by combined MRI in 6.6%/7.3% of patients with nr-axSpA.

Conclusions

Combined spine and SIJ MRI added little incremental value compared with SIJ MRI alone for diagnosing patients with nr-axSpA and enhancing confidence in this diagnosis.

Fat infiltration on magnetic resonance imaging of the sacroiliac joints has limited diagnostic utility in nonradiographic axial spondyloarthritis

OBJECTIVE

To explore whether morphological features of fat infiltration (FI) on sacroiliac joint (SIJ) magnetic resonance imaging (MRI) contribute to diagnostic utility in 2 inception cohorts of patients with nonradiographic axial spondyloarthritis (nr-axSpA).

METHODS

Four blinded readers assessed SIJ MRI in 2 cohorts (A/B) of 157 consecutive patients with back pain who were ≤ 50 years old, and in 20 healthy controls. Patients were classified according to clinical examination and pelvic radiography as having nr-axSpA (n = 51), ankylosing spondylitis (n = 34), or nonspecific back pain (n = 72). Readers recorded FI, bone marrow edema (BME), and erosion, predefined morphological features of FI (distinct border, homogeneity, subchondral location), and anatomical distribution of SIJ FI. The proportion of SIJ quadrants affected by FI and frequencies of various SIJ FI features were analyzed descriptively. We calculated positive/negative likelihood ratios (LR) to estimate the diagnostic utility of various features of FI, with and without associated BME, and erosion.

RESULTS

Of the patients with nr-axSpA in cohorts A/B, 45.0%/48.4% had FI in ≥ 2 SIJ quadrants. Of those, 25.0%/22.6% and 20.0%/25.8% showed FI with distinct border or homogeneous pattern, respectively, and 50% to 100% of those patients displayed concomitant BME or erosion. FI per se in ≥ 2 SIJ quadrants had no diagnostic utility (LR+ 1.62/1.91). FI with distinct border (LR+ 8.29/2.13) or homogeneity (LR+ 6.24/3.78) demonstrated small to moderate diagnostic utility.

CONCLUSION

SIJ FI per se was not of clinical utility in recognition of nr-axSpA. Distinct border or homogeneity of FI on SIJ MRI showed small to moderate diagnostic utility in nr-axSpA, but were strongly associated with concomitant BME or erosion, highlighting the contextual interpretation of SIJ MRI.

Development, sensibility, and reliability of the Toronto Axial Spondyloarthritis Questionnaire in inflammatory bowel disease

OBJECTIVE

There is an unacceptable delay in the diagnosis of axial spondyloarthritis (axSpA) in its early stages among patients at high risk, in particular those with inflammatory bowel disease (IBD). Our objectives were to develop a sensible and reliable questionnaire to identify undetected axSpA among patients with IBD.

METHODS

Literature was reviewed for item generation in the Toronto axSpA Questionnaire on IBD (TASQ-IBD). Sensibility of the questionnaire was assessed among healthcare professionals and patients. This assessment was related to purpose and framework (clinical function, clinical justification, and clinical applicability), face validity, comprehensiveness [oligo-variability (limiting the questionnaire to important items) and transparency], replicability, content validity, and feasibility. The test-retest reliability study was administered to 77 patients with established IBD and axSpA. Kappa agreement coefficients and absolute agreement were calculated for items.

RESULTS

Three domains included IBD, inflammatory back symptoms, and extraaxial features. The entry criterion required a patient to have IBD and back pain or stiffness that ever persisted for ≥ 3 months. Iterative sensibility assessment involved 16 items and a diagram of the back. Kappa coefficients ranged from 0.81-1.00 for each item. Absolute agreement across all items ranged from 91% to 100%.

CONCLUSION

TASQ-IBD is a newly developed, sensible, and reliable case-finding questionnaire to be administered to patients with IBD who have ever had chronic back pain or stiffness persisting for ≥ 3 months. It should facilitate identification and timely referral of patients with IBD to rheumatologists and minimize the delay in diagnosis of axSpA. Consequently, it should assess the prevalence of axSpA in IBD.

A registry of ankylosing spondylitis registries and prospects for global interfacing

PURPOSE OF REVIEW

To review the optimal criteria and conditions for establishing a clinical registry, as well as detailing their application in a number of ankylosing spondylitis (AS) and axial spondyloarthritis (axSpA) Registries already in existence.

RECENT FINDINGS

Recent genetic studies and studies of long-term treatment efficacy and side-effects have underscored the need for large numbers of patients, much larger than would be possible from a single center or consortium. An optimal Registry should have its aims established upfront, with appropriate governance and oversight, and inclusion and exclusion criteria for participating collaborators and subject defined. Collaborators contributing subjects to a Registry should use validated instruments for which they have been previously trained. The numerous cross-sectional and longitudinal Registries on AS and axSpA have been recently established that differ widely depending on the referral and selection issues.

SUMMARY

The challenge of large-scale examinations of genetics, comorbidities, medication usage, and side-effects in spondyloarthritis underscores the need for combining data from well characterized registries of AS patients which require careful planning. There are currently many such registries available internationally, offering promise for collaborations and data pooling that can answer some of the pressing questions facing rheumatology clinicians and researchers.