Is it Useful to Repeat Magnetic Resonance Imaging of the Sacroiliac Joints After Three Months or One Year in the Diagnosis of Patients With Chronic Back Pain and Suspected Axial Spondyloarthritis?

OBJECTIVE: To investigate the value of repeated magnetic resonance imaging (MRI) of the sacroiliac (SI) joints in diagnosing chronic back pain patients in whom axial spondyloarthritis (SpA) is suspected and to examine determinants of positive MRI findings in SI joints. METHODS: Patients with chronic back pain (duration 3 months-2 years, age ≥16 years, age at onset <45 years) with ≥1 SpA feature who were included in the Spondyloarthritis Caught Early cohort underwent visits at baseline, at 3 months, and at 1 year. Visits included an evaluation of all SpA features and repeated MRI of SI joints. MRI-detected axial SpA positivity (according to the definition from the Assessment of SpondyloArthritis international Society) was evaluated by 2 or 3 well-trained readers who were blinded with regard to clinical information. The likelihood of a positive MRI finding at follow-up visits (taking into consideration contributing factors) was calculated by generalized estimating equation analysis. RESULTS: Of the 188 patients, 38.3% were male, the mean ± SD age was 31.0 ± 8.2 years, and the mean ± SD symptom duration was 13.2 ± 7.1 months. Thirty-one patients (16.5%) had positive MRI findings in the SI joints at baseline. After 3 months and after 1 year, the MRI results had changed from positive to negative in 3 of 27 patients (11.1%) and 11 of 29 patients (37.9%), respectively, which was attributable in part to the initiation of anti-tumor necrosis factor therapy. Status changes from negative to positive were seen in 5 of 116 patients (4.3%) after 3 months and in 10 of 138 patients (7.2%) after 1 year. HLA-B27 positivity and male sex were independent determinants of the likelihood of a positive MRI scan at any time point (42% in HLA-B27+ men and 6% in HLA-B27- women). If the baseline results were negative, the likelihood of a positive scan at follow-up was very low (≤7%). CONCLUSION: MRI-detected status changes in the SI joints were seen in a minority of the patients, and both male sex and HLA-B27 positivity were important predictors of MRI positivity. Our findings indicate that conducting MRI scans after 3 months or after 1 year in patients with suspected early axial SpA is not diagnostically useful.

Presence of multiple spondyloarthritis (SpA) features is important but not sufficient for a diagnosis of axial spondyloarthritis: data from the SPondyloArthritis Caught Early (SPACE) cohort.

OBJECTIVES: Concerns have been raised about overdiagnosis of axial spondyloarthritis (axSpA). We investigated whether patients with chronic back pain (CBP) of short duration and multiple SpA features are always diagnosed with axSpA by the rheumatologist, and to what extent fulfilment of the Assessment of SpondyloArthritis International Society (ASAS) axSpA criteria is associated with an axSpA diagnosis. METHODS: Baseline data from 500 patients from the SPondyloArthritis Caught Early cohort which includes patients with CBP (≥3 months, ≤2 years, onset <45 years) were analysed. All patients underwent full diagnostic workup including MRI of the sacroiliac joints (MRI-SI) and radiograph of sacroiliac joints (X-SI). For each patient, the total number of SpA features excluding sacroiliac imaging and human leucocyte antigen B27 (HLA-B27) status was calculated. RESULTS: Before sacroiliac imaging and HLA-B27 testing, 32% of patients had ≤1 SpA feature, 29% had 2 SpA features, 16% had 3 SpA features and 24% had ≥4 SpA features. A diagnosis of axSpA was made in 250 (50%) of the patients: 24% with ≤1 SpA feature, 43% with 2 SpA features, 62% with 3 SpA features and 85% with ≥4 SpA features. Of the 230 patients with a positive ASAS classification 40 (17.4%) did not have a diagnosis of axSpA. HLA-B27 positivity (OR 5.6; 95% CI 3.7 to 8.3) and any (MRI-SI and/or X-SI) positive imaging (OR 34.3; 95% CI 17.3 to 67.7) were strong determinants of an axSpA diagnosis. CONCLUSIONS: In this cohort of patients with CBP, neither the presence of numerous SpA features nor fulfilment of the ASAS classification criteria did automatically lead to a diagnosis axSpA. Positive imaging was considered particularly important in making a diagnosis of axSpA.

Are Additional Tests Needed to Rule Out Axial Spondyloarthritis in Patients Ages 16-45 Years With Short-Duration Chronic Back Pain and Maximally One Spondyloarthritis Feature?

OBJECTIVE: To investigate whether HLA-B27 testing and imaging of the sacroiliac joints are needed in patients with ≤1 spondyloarthritis (SpA) feature, referred to a secondary care setting, after medical history collection, clinical examination, and measurement of acute phase reactants. METHODS: Baseline data from patients in the Spondyloarthritis Caught Early (SPACE) cohort visiting the rheumatology outpatient clinic of 5 centers across Europe (with back pain ≥3 months, ≤2 years, onset at ages <45 years) were used. All patients underwent a full diagnostic work-up: magnetic resonance imaging (MRI) and radiographs of the sacroiliac joints, HLA-B27 testing, and assessment of all other SpA features. Patients were diagnosed according to the treating rheumatologist and classified according to the Assessment of SpondyloArthritis international Society (ASAS) axial SpA criteria. RESULTS: Of the 354 patients, 133 (37.5%) showed 0 or 1 SpA feature after medical history collection, physical examination, and measurement of acute phase reactants (38 without SpA features, 95 with 1 SpA feature). Of the patients with ≤1 SpA feature, 18.4% (with 0 SpA features) and 17.9% (with 1 SpA feature) were diagnosed with axial SpA according to the rheumatologist after additional investigations (HLA-B27 testing and sacroiliac joint imaging). Additionally, 4 of 38 patients (10.5%) without SpA features fulfilled the ASAS axial SpA criteria (all according to the imaging arm only: 2 as MRI+/modified New York criteria (mNY)+, 1 as MRI+/mNY-, and 1 as MRI-/mNY+). Of the 95 patients with 1 SpA feature, 22 (23.2%) fulfilled the ASAS axial SpA criteria (all according to the imaging arm only: 3 as MRI+/mNY+, 15 as MRI+/mNY-, and 4 as MRI-/mNY+). CONCLUSION: In these patients in a secondary care setting with ≤1 SpA feature, axial SpA could not be ruled out without sacroiliac joint imaging and/or HLA-B27 testing.