Patients with fibromyalgia rarely fulfil classification criteria for axial spondyloarthritis.

Background: The Assessments of Spondyloarthritis international Society (ASAS) classification criteria for axial spondyloarthritis (axSpA) have been criticized because of insufficient differentiation towards FM. The aim of this study was to compare the performance of currently used classification criteria in patients diagnosed with axSpA or FM. Methods: Patients were prospectively included if diagnosed with axSpA or FM by the treating rheumatologist and evaluated by an independent examiner for fulfilment of the classification criteria for axSpA (ASAS criteria) and/or FM (1990 ACR classification and 2010 ACR diagnostic criteria). Patients with axSpA were stratified based on classification as non-radiographic axSpA (nr-axSpA) or AS. Symptom severity was assessed by established disease-related questionnaires. Results: Overall, 300 patients were included, 100 with FM and 200 with axSpA of which 100 each had nr-axSpA and AS. Almost all FM patients fulfilled the 2010 (100%) and 1990 ACR criteria (98%) for FM, but only 2% fulfilled the ASAS criteria. When calculations were based on only the FM patients with available HLA-B27 results (n = 40), the proportion fulfilling the ASAS criteria was 5%. All axSpA patients met the ASAS criteria but also the 2010 (24%) and 1990 (13.5%) FM criteria. More patients with AS (29% and 19%) than with nr-axSpA (19% and 8%) fulfilled the 2010 and 1990 FM criteria, respectively. Conclusion: FM patients only rarely fulfil classification criteria for axSpA but some axSpA patients also fulfil FM criteria. Since this was more frequent in patients with AS it may be related to the severity and duration of chronic pain in axSpA patients. Assessment instruments evaluated in axSpA are not disease-specific. The phenomenon of central pain sensitization in rheumatic diseases deserves more study.

Chronic but not inflammatory changes at the Achilles' tendon differentiate patients with peripheral spondyloarthritis from other diagnoses - Results from a prospective clinical trial.

BACKGROUND: Imaging has an essential role in the new spondyloarthritis (SpA) classification criteria for axial but not for peripheral manifestations. We evaluated the impact of imaging findings for identification and treatment decisions in patients with peripheral spondyloarthritis (pSpA) and controls (non-SpA). METHODS: Patients with pSpA (Assessment of SpA international Society criteria, n=30) and non-SpA (n=30), aged <45 years, with painful heels or knees, were recruited. Conventional radiography, grey-scale ultrasound including power Doppler (US/PDUS) and MRI of symptomatic areas were performed to assess inflammatory and structural changes. Mann-Whitney U test was used for group comparisons. RESULTS: In total, 105 painful entheses (71 heels, 34 knees) in 60 patients were examined. Differences between diagnoses were found for symptom duration (pSpA: 17.2±27.5 vs non-SpA: 4.4±4.3 months), human leucocyte antigen B27 prevalence (67% vs 13%) and gender distribution (53.3% vs 20% male, respectively), all P<0.05. Logistic regression analysis for baseline differences showed that chronic changes (erosions and calcification) in the heel were more frequent in pSpA versus non-SpA by US/PDUS (62.5% vs 28.6% patients and 59.5% vs 26.5% entheses, P<0.05). Inflammatory changes in heel or knee by US/PDUS and MRI could not differentiate between non-SpA and pSpA. CONCLUSIONS: Differentiation between pSpA and non-SpA was only possible based on structural but not inflammatory changes in the heels and knees of symptomatic patients. US/PDUS was superior to MRI for this purpose. These findings imply that pSpA is associated with erosive changes at enthesitic sites, while inflammation and susceptibility are of minor influence for the development of erosions and calcification to pSpA.

Efficiency of treatment with non-steroidal anti-inflammatory drugs according to current recommendations in patients with radiographic and non-radiographic axial spondyloarthritis.

OBJECTIVE: NSAIDs are first-line therapy in axial SpA (axSpA). The proportion of patients responding to NSAIDs and differences between AS and non-radiographic axSpA (nr-axSpA) in this regard have not been studied in detail to date. The aim of this study was to examine the proportion of patients with AS and nr-axSpA responding to NSAIDs according to current treatment recommendations. METHODS: Consecutive anti-TNF-naïve patients with nr-axSpA and AS (n = 50 each) were included if their BASDAI score was ⩾4 without having received maximal NSAID doses. In case of a BASDAI score ⩾4 1 week later, another NSAID was prescribed. For the next 3 weeks, continuous intake of maximal doses was recommended but patients could reduce doses in case of intolerance or improvement. MRI of the SI joints was performed at baseline and week 4. RESULTS: All outcomes except for CRP and MRI scores improved significantly after 4 weeks of NSAIDs, with no difference between axSpA subgroups. An Assessment of SpondyloArthritis international Society 40% (ASAS40) response and partial remission rates were 35 and 16% at week 4, respectively. At the same time point, a BASDAI score ⩾4 was still present in 44% of patients, 30% of which had reduced NSAID doses, partly due to intolerance (38%). Only 13% of all patients had continuously taken NSAIDs at the maximal dosage, but there was no difference in the efficacy outcome compared with those who had taken reduced doses. CONCLUSION: AS and nr-axSpA patients had similar response rates to NSAIDs while objective signs of inflammation did not change over 4 weeks. Only a minority of patients was willing to take maximal doses of NSAIDs, and ⩾40% patients remained candidates for TNF blockers. These results may influence future trial designs.

Quantification of Bone Marrow Edema by Magnetic Resonance Imaging Only Marginally Reflects Clinical Neck Pain Evaluation in Rheumatoid Arthritis and Ankylosing Spondylitis.

OBJECTIVE: Neck pain is common in rheumatoid arthritis (RA) and ankylosing spondylitis (AS). We investigated the correlation of bone marrow edema (BME) on magnetic resonance imaging (MRI) in RA and AS and its association with clinical complaints of neck pain. METHODS: Cervical spine short-tau inversion recovery-MRI and T1w-MRI of 34 patients with RA and 6 patients with AS complaining about neck pain were obtained. Clinical and laboratory data were available. BME was scored by 2 blinded readers using a modification of a published score, including various cervical sites. Degenerative changes were also quantified. RESULTS: Patients were predominantly women (82.5%), and mean ± SD age was 57.5 ± 11.8 years, C-reactive protein (CRP) was 0.8 ± 1.3 mg/dl, and pain score was 46.0 ± 17.5. BME was detected in 24/40 patients (60%) involving the atlantoaxial region (21%), vertebral bodies (75%), facet joints (29%), and spinous processes (46%). Degenerative changes were identified in 21/40 patients (52.5%), 13 (62%) of whom also had BME in vertebral bodies. No differences were found between patients with versus without cervical BME for clinical assessments: numeric rating scale pain (median ± interquartile range) 5.5 ± 3.0 vs 6.0 ± 4.0 (p = 0.69), Funktionsfragebogen Hannover 68.2 ± 41.0 vs 42.0 ± 55.5 (p = 0.19), Northwick pain score 44.4 ± 21.8 vs 47.2 ± 27.0 (p = 0.83), or CRP 0.40 ± 0.80 vs 0.60 ± 0.66 (p = 0.94). For patients with degenerative changes, symptom duration was longer than for patients without (10 ± 12.5 vs 5.0 ± 18.0 yrs, p = 0.73). CONCLUSION: In this small study of patients with RA and AS complaining about neck pain, BME was found in many different cervical sites, including the facet joints and the spinous processes. However, the occurrence and severity of BME did not correlate with the severity of neck pain.

Do patients with non-radiographic axial spondylarthritis differ from patients with ankylosing spondylitis?

OBJECTIVE: Patients with axial spondylarthritis (SpA) who have structural changes in the sacroiliac joints and/or the spine have been classified as having ankylosing spondylitis (AS), while those without such changes are now classified as having nonradiographic axial SpA (nr-axSpA). The differentiating features are incompletely understood. METHODS: Data from 100 consecutive patients with axial SpA not treated with tumor necrosis factor antagonists were compared clinically and with laboratory parameters, spinal radiographs, and magnetic resonance imaging (MRI) of the spine. Standardized clinical assessment tools were used to assess health status. RESULTS: AS was diagnosed in 56 patients and nr-axSpA in 44 patients. Signs of inflammation were significantly higher in patients with AS than in patients with nr-axSpA, with a median C-reactive protein level of 8.0 versus 3.8 mg/liter, a median Ankylosing Spondylitis Disease Activity Score of 2.2 versus 2.8, respectively, and a median amount of spinal inflammatory lesions on MRI of 2.0 versus 0.0, respectively. Significant differences between these 2 groups were seen in sex (76.8% male AS patients versus 31.8% male nr-axSpA patients). Clinical variables did not differ between patients with AS and nr-axSpA (Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, Ankylosing Spondylitis Quality of Life questionnaire, Short Form 36 health survey). CONCLUSION: Patients with nr-axSpA were characterized by the low proportion of male patients and the low burden of inflammation compared to patients with AS. While both groups did not differ regarding health status, disease activity, and physical function, they did differ in signs of inflammation; all were higher in patients with AS. Since many patients with nr-axSpA had not developed structural changes after years of symptoms, we propose that those patients should not be regarded as having preradiographic AS but rather as having nr-axSpA.