BackgroundThe value of clinical items defining inflammatory back pain to identify patients with axial spondyloarthritis (SpA) in primary care is unclear.ObjectiveTo identify predictive clinical parameters for a diagnosis of axial SpA in patients with chronic back pain presenting in primary care.MethodsConsecutive patients aged <45 years (n=950) with back pain for >2 months who presented to orthopaedic surgeons (n=143) were randomised based on four key questions for referral to rheumatologists (n=36) for diagnosis.ResultsThe rheumatologists saw 322 representative patients (mean age 36 years, 50% female, median duration of back pain 30 months). 113 patients (35%) were diagnosed as axial SpA (62% HLA B27+), 47 (15%) as ankylosing spondylitis (AS) and 66 (21%) as axial non-radiographic SpA (nrSpA). Age at onset ≤35 years, improvement by exercise, improvement with non-steroidal anti-inflammatory drugs, waking up in the second half of the night and alternating buttock pain were identified as most relevant for diagnosing axial SpA by multiple regression analysis. Differences between AS and nrSpA were detected. No single item was predictive, but ≥3 items proved useful for good sensitivity and specificity by receiver operating characteristic modelling.ConclusionThis study shows that a preselection in primary care of patients with back pain based on a combination of clinical items is useful to facilitate the diagnosis of axial SpA.

This is the first study to show that patients with axSpA are more reliably identified in primary care by a strategy that includes HLA B27. Because of the two-step approach, the test needs to be performed in only about half of patients with chronic BP.

BackgroundImaging 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).MethodsPatients 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.ResultsIn 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.ConclusionsDifferentiation 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.

BackgroundBoth patients with axial spondyloarthritis (axSpA) and patients with fibromyalgia (FM) are suffering from pain. The new ASAS classification criteria for axSpA have been recently challenged by arguing that FM patients could easily fulfill the clinical arm of the criteria, which could lead to overdiagnosis of axSpA and wrong treatment decisions.ObjectivesTo study similarities and differences between axSpA and FM using different sets of classification criteria and to assess the severity of wide-spread pain in both diseases.MethodsIn this prospective study, patients were consecutively included if they were diagnosed with axSpA, or FM by a rheumatologist. Patients with rheumatoid arthritis (RA) were also included as an inflammatory control group. Patients on anti-TNF treatment were not included. Established classification and outcome parameters as well as standardized instruments were used in all patients. MRIs were performed in all axSpA and 20 FM patients. All axSpA and FM patients had radiographs. The Mann-Whitney-U test was used for statistical comparisons between groups.ResultsA total of 214 patients was included: 93 with FM (7.5% HLA B27+), 91 with axSpA (79.1% HLA-B27+) and 30 with RA (53.3% seropositive). The mean age was 50.7±9.1, 43.0±12 and 58.4±11.9 years, respectively, and the mean symptom duration was comparable between groups: 6.6±6.9, 6.4±7.8 and 6.2±11.3, respectively. Expectedly, the gender ratio differed: FM and RA patients were mostly female (93.4% and 76.7%, respectively), as compared to axSpA patients (28.3%). The ASAS classification criteria were not fulfilled by any FM patient. In contrast, the 1990 and 2010 FM criteria were fulfilled by 98.3% and 100% of patients with FM, but also by 14.3% and 34.1% of axSpA (no differences between AS and nr-axSpA) and 30% and 46.7% of RA patients, respectively. The Fibromyalgia impact questionnaire (FIQ) values were 69.5±13.0, 45.4±19.3 (p<0.001) and 49.9±22.8, respectively, while the Health Assessment Questionnaire (HAQ) values were 1.7±0.5, 1.2±0.5 (p<0.001) and 1.6±0.8, for FM, axSpA and RA, respectively. FM patients reported the highest pain scores on a 0-10 numeric rating scale: 7.0±1.7 vs. 6.0±1.9 and 6.1±1.9 in axSpA and RA patients, respectively, while mean CRP values (mg/dl) were higher in axSpA (1.1±1.3) and RA (0.6±0.9) patients vs. FM (0.4±0.4) (both p<0.001).ConclusionsImportantly, no FM patients fulfilled ASAS classification criteria. Only a small proportion of patients with axSpA fulfilled any of the FM classification criteria. There was less overlap between patients with FM, axSpA and RA using the 1990 criteria as compared to the more sophisticated 2010 FM criteria. FM patients reported higher pain scores and more functional deficits. Some patients with widespread pain may have underlying axSpA - this differential diagnosis needs to be taken into account when dealing with the diagnosis of FM in daily practice.Disclosure of InterestNone declared

Background Measures for disease activity (BASDAI, ASDAS) are routinely used in patients (pts) with axial spondyloarthritis (axSpA). The ASDAS, a composite score that includes clinical measures and CRP, has high discriminatory capacity for assessment of disease activity. Clinical trial data showed that the ASDAS has a better sensitivity to change than the BASDAI in pts treated with TNF-blockers. However, there are no data on the comparison of ASDAS and BASDAI in axSpA pts treated with NSAIDs, which are recommended as first choice prior to a possible initiation of TNF-blockers. Objectives We compared the performance of BASDAI and ASDAS in assessing and predicting clinical response to intensive NSAID treatment in axSpA pts with high disease activity. Methods Consecutive pts with nr-axSpA and AS (n=50 each group) were included in a prospective study if their BASDAI level was ≥4, if they had not yet received the maximally approved dose of NSAIDs and if they had not been treated with anti-TNF agents to date. After inclusion the maximal dose of NSAIDs was administered over one week (wk) and the dose was then reduced in case of BASDAI <4 or, in case of BASDAI ≥4, the NSAID was changed and pts were treated for another 3 wks at maximal doses. Clinical and laboratory parameters were assessed and the dosage of NSAIDs was quantified by using the ASAS-index. Data were collected before (BL) and after 1 and 4 wks of NSAID treatment. Results Baseline characteristics of AS and nr-axSpA patients were similar. Prior to treatment, an ASDAS >2.1 was found in 74% and 76% of pts with AS and nr-axSpA, respectively. There was a significant decrease in both, ASDAS (BL: 2.5±0.6, 1wk: 1.9±0.8, 4wk: 1.6±0.8) and BASDAI (BL: 5.8±1.3 1wk: 4.1±2.1 4wk: 2.1±3.1). At wks 1 and 4, a BASDAI <3 was achieved by 20% and 22% of AS and 15% and 18% of nr-axSpA pts, respectively. An ASDAS <2.1 was reached by 29% and 34% of AS and 34% and 33% of nr-axSpA pts, respectively. An ASDAS <1.3 indicative of inactive disease was found in 13% and 16% of AS and 15% and 18% of nr-axSpA pts, respectively. However, at wk 4 a BASDAI ≥4 was still present in 34% axSpA pts, but only 15% of these had an ASDAS <2.1. Another 33% of pts had an ASDAS <2.1 but only 4% of those had a BASDAI <4. This difference was much more prominent in nr-axSpA patients (Table). In the univariate logistic regression analysis both, ASDAS (OR: 3.6, p=0.002) and BASDAI (OR: 1.8, p=0.001) predicted the eligibility for anti-TNF therapy after 4wk of NSAIDs at BL, ASDAS performed superior to BASDAI. ASDAS ≥2.1 ASDAS<2.1 AS BASDAI ≥4 14% 7% BASDAI <4 2% 27% nr-axSpA BASDAI ≥4 15% 25% BASDAI <4 2% 8% Conclusions BASDAI and ASDAS showed a similar magnitude of response on NSAID treatment in both AS and nr-axSpA. Of interest, the discriminative power of the ASDAS was much clearer in patients classified as nr-axSpA and especially in those who could be considered as candidates for anti-TNF treatment. These data challenge the concept of only using the BASDAI cut-off ≥4 for such t...