ABSTRACT
OBJECTIVES: The aim of the current study was to investigate the diagnostic value of three sacroiliac (SI) joint pain provocation tests for sacroiliitis identified by magnetic resonance imaging (MRI) and stratified by gender. METHOD: Patients without clinical signs of nerve root compression were selected from a cohort of patients with persistent low back pain referred to an outpatient spine clinic. Data from Gaenslen's test, the thigh thrust test, and the long dorsal sacroilia ligament test and sacroiliitis identified by MRI were analysed. RESULTS: The median age of the 454 included patients was 33 (range 18-40) years and 241 (53%) were women. The prevalence of SI joints with sacroiliitis was 5%. In the whole study group, only the thigh trust test was associated with sacroiliitis, the area under the receiver operating characteristic (ROC) curve (AUC) was 0.58 [95% confidence interval (CI) 0.51-0.65], sensitivity 31% (95% CI 18-47), and specificity 85% (95% CI 82-87). In men, sacroiliitis was associated with all the SI joint tests assessed and multi-test regimens, with the greatest AUC found for at least one positive out of three tests [AUC 0.68 (95% CI 0.56-0.80), sensitivity 56% (95% CI 31-79), and specificity 81% (95% CI 77-85)]. In women, no significant associations were observed between the SI joint tests and sacroiliitis. CONCLUSIONS: Only in men were the SI joint tests found to be associated with sacroiliitis identified by MRI. Although, the diagnostic value was relatively low, the results indicate that the use of SI joint tests for sacroiliitis may be optimized by gender-separate analyses.
Subject(s)
Magnetic Resonance Imaging/methods , Sacroiliac Joint/diagnostic imaging , Sacroiliitis/diagnostic imaging , Adult , Area Under Curve , Female , Humans , Male , Sex CharacteristicsABSTRACT
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.
Subject(s)
Antibodies, Bacterial/immunology , Klebsiella pneumoniae/immunology , Low Back Pain/immunology , Sacroiliitis/immunology , Spondylarthropathies/immunology , Adolescent , Adult , Bacterial Capsules/immunology , C-Reactive Protein/immunology , Case-Control Studies , Denmark , Female , HLA-B27 Antigen/genetics , Humans , Immunoglobulin A/immunology , Immunoglobulin G/immunology , Magnetic Resonance Imaging , Male , Sacroiliitis/diagnostic imaging , Sacroiliitis/genetics , Serogroup , Spondylarthropathies/diagnostic imaging , Spondylarthropathies/genetics , Spondylitis, Ankylosing/diagnostic imaging , Spondylitis, Ankylosing/genetics , Spondylitis, Ankylosing/immunology , Young AdultABSTRACT
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.
