Louise Thuesen Hermansen

Associations Between Spondyloarthritis Features and Magnetic Resonance Imaging Findings: A Cross-Sectional Analysis of 1,020 Patients With Persistent Low Back Pain

The Assessment of SpondyloArthritis international Society (ASAS) has previously published criteria for spondyloarthritis (SpA). In the Spines of Southern Denmark cohort, which included patients with persistent low back pain and an unknown proportion of patients with SpA, our objectives were 1) to estimate the prevalence of magnetic resonance imaging (MRI) findings and clinical features included in the ASAS criteria for SpA and 2) to explore the associations between MRI findings and clinical features.

Associations between spondyloarthritis features and MRI findings: A cross‐sectional analysis of 1020 patients with persistent low back pain

The Assessment of SpondyloArthritis international Society (ASAS) has previously published criteria for spondyloarthritis (SpA). In the Spines of Southern Denmark cohort, which included patients with persistent low back pain and an unknown proportion of patients with SpA, our objectives were 1) to estimate the prevalence of magnetic resonance imaging (MRI) findings and clinical features included in the ASAS criteria for SpA and 2) to explore the associations between MRI findings and clinical features.

Limited Reliability of Radiographic Assessment of Sacroiliac Joints in Patients with Suspected Early Spondyloarthritis

Objective. To determine the reproducibility of evaluation of sacroiliac joint (SIJ) radiographs among readers with varying levels of experience, and to identify potential drivers of disagreement in classification among 5 predefined radiographic lesion types. Methods. The study sample consisted of 104 consecutive patients aged 18–40 with low back pain ≥ 3 months of duration who met the Assessment of SpondyloArthritis international Society (ASAS) definition for a positive SIJ magnetic resonance image, or were HLA-B27–positive and had ≥ 1 spondyloarthritis (SpA)-related clinical/laboratory feature according to the ASAS classification criteria for axial SpA. Seven blinded readers (2 musculoskeletal radiologists, 5 rheumatologists) classified pelvic radiographs according to the modified New York criteria (mNY) and recorded presence/absence of 5 lesion types in both SIJ: erosion, sclerosis, ankylosis, joint space widening, and joint space narrowing. Reproducibility of mNY classification among 21 reader pairs was assessed and potential drivers of disagreement were identified among 5 lesion types. A generalized linear mixed logistic regression model served to analyze to what extent discordance in lesion type was associated with discrepant mNY classification. Results. Mean κ values (percent concordance) were 0.39 (84.1%) for mNY classification over 21 reader pairs, 0.46 (79.8%) between 2 musculoskeletal radiologists, and 0.55 (86.5%) and 0.36 (77.9%) between the most experienced rheumatologist and the 2 radiologists. Erosion showed the lowest agreement (25%) among patients with discordant classification and gave the highest OR of 13.5 for disagreement. Conclusion. Reproducibility of radiographic SIJ classification in an SpA inception cohort was only fair to at best moderate among 7 readers with varying levels of experience, questioning the applicability of mNY in early SpA.

The discriminative value of inflammatory back pain in patients with persistent low back pain

Objectives: To estimate the prevalence of inflammatory back pain (IBP) characteristics and analyse the discriminative value of IBP relative to axial spondyloarthritis (SpA) according to the Assessment of SpondyloArthritis international Society (ASAS) criteria. Method: Patients who had low back pain for > 3 months were selected from a cohort of secondary care patients aged 18–40 years. Data included information on SpA features, human leucocyte antigen (HLA)-B27 typing, C-reactive protein (CRP) level, magnetic resonance imaging (MRI) of the sacroiliac joints, and self-reported IBP questions covering the pain characteristics included in the Calin, Berlin, and ASAS IBP definitions. Results: Of the 759 included patients, 99% [95% confidence interval (CI) 98–100] had at least one IBP characteristic. The prevalence of the single IBP characteristics ranged from 10% (95% CI 7–12) for ‘pain worst in the morning’ to 79% (95% CI 76–82) for ‘morning stiffness’. Two-thirds of the patients (67%, 95% CI 63–70), met at least one of the three IBP definitions. In all, 86 (11%) were classified as ‘SpA according to ASAS’. All three IBP definitions were significantly associated with ‘SpA according to ASAS’; however, the discriminative value was low, with sensitivity, specificity, and balanced accuracy values of 64, 50, and 57% for Calin, 59, 60, and 60% for Berlin, and 35, 79, and 57% for ASAS IBP definitions, respectively. Conclusions: In this study population, IBP characteristics were in general common and the discriminative value was low, as IBP could not differentiate patients with SpA according to ASAS criteria from patients with other causes of back pain.

No diagnostic utility of antibody patterns against Klebsiella pneumoniae capsular serotypes in patients with axial spondyloarthritis vs. patients with non-specific low back pain: a cross-sectional study

Objectives: To investigate whether antibody response patterns against Klebsiella pneumoniae capsular serotypes can discriminate patients with axial spondyloarthritis (axSpA) from patients with non-specific low back pain (LBP). Method: Immunoglobulin (Ig)G and IgA antibodies against K. pneumoniae capsular serotypes K2, K26, K36, and K50 were measured, and antibody seropositivity compared between groups and analysed for patient correlation in five different groups: (a) 96 patients fulfilling the Assessment of SpondyloArthritis International Society (ASAS) classification criteria for axSpA; (b) 38 patients with either a positive magnetic resonance imaging (MRI) scan as defined by ASAS or a positive human leucocyte antigen (HLA)-B27 status plus one clinical SpA feature, characterized as ‘non-axSpA’; (c) 82 non-specific LBP patients; (d) 40 healthy blood donors and (e) 43 patients with diagnosed ankylosing spondylitis (AS) served as the negative and positive control groups. Results: There was no difference in IgG and IgA seropositivity against all serotypes between the axSpA, non-axSpA, and LBP groups. No significant correlations were found between anti-Klebsiella antibodies and age, gender, HLA-B27, or high-sensitivity C-reactive protein (hsCRP). IgG seropositivity against K50 was more frequent in AS (25.6%) than in axSpA (13.5%, p < 0.05). axSpA patients with radiographic sacroiliitis and AS controls concordantly had the highest frequency of seropositivity for ≥ 2 serotypes (21%). Conclusions: The antibody patterns against K. pneumoniae serotypes K2, K26, K36, and K50 did not discriminate between early axSpA and non-specific LBP.

The size and frequency of bone marrow oedema on sacroiliac joint mri differs in a cluster-wise comparison of patients with findings suggestive of axial spondyloarthritis

Background Multiple correspondence analysis (MCA) is a statistical method that allows for the translation of data from multiple categorical variables into single coordinates per individual. When combined with cluster analysis, individuals that share phenotypic characteristics can be grouped together. The Assessment of Axial Spondyloarthritis international Society (ASAS) published classification criteria for axial spondyloarthritis (axSpA) in 20091 that included active sacroiliitis on magnet resonance imaging (MRI) of the sacroiliac joints (SIJ) defined as bone marrow oedema (BME) present in either as 2 lesions on one slice, or 1 lesion on 2 consecutive slices.2 It has been shown that extent of BME is associated with risk of radiographic progression.3 Objectives To identify phenotypes in low back pain (LBP) patients recruited from primary care with findings suggestive of early axSpA and to assess differences in size and frequency of BME lesions on SIJ MRI. Methods Age, gender and the ASAS SpA features (SIJ BME on MRI, HLA-B27, inflammatory back pain, arthritis, heel enthesitis, uveitis, psoriasis, inflammatory bowel disease, good response to NSAIDs, family history of SpA, but not dactylitis (not observed) or radiographic sacroiliitis) of 134 LBP patients who either met of were one feature short of meeting the ASAS classification criteria for axSpA were analysed by MCA and subsequent k-means cluster analysis in order to identify various clinical phenotypes. The above listed SpA features, and if present, the size and frequency of SIJ BME as defined by the Aarhus scoring module,4 were compared across clusters. Results MCA and cluster analysis revealed 3 clusters. Cluster 1 was predominantly HLA-B27 positive (96.7%) with SIJ BME in half of the cases. Cluster 2 and 3 had SIJ BME in all cases. Cluster 3 had fewer features suggestive of axSpA than clusters 1 and 2. There were significant differences in frequency (3.0 vs 2.0 vs 1.0) and extent of BME (4.0 vs 2.0 vs 1.0) across clusters 1, 2 and 3.Abstract THU0240 – Table 1 Cluster-wise comparison of the construction variables, frequency and size of sacroiliac joint bone marrow oedema* Conclusions Three clusters were identified among LBP patients with findings suggestive of axSpA: 1 predominantly HLA-B27 positive cluster with SIJ BME in half of the subjects, and 2 clusters having less features suggestive of SpA and with SIJ BME in all subjects. The predominantly HLA-B27 positive cluster had more and larger BME lesions than the other 2, which may indicate individuals at risk for progression. References [1] Ann Rheum Dis2009;68(6):777–83; [2] Ann Rheum Dis2009;68(10):1520–7. [3] Arthritis Rheum2008;58(11):3413–3418. [4] AC&R. 2010;62(1):11–8. Disclosure of Interest None declared