L. Van Hoeven

Evaluating the ASAS recommendations for early referral of axial spondyloarthritis in patients with chronic low back pain; is one parameter present sufficient for primary care practice?

New diagnostic tools and effective treatment for axial spondyloarthritis (axSpA) became available in the last decade. This has raised the need for adequate referral strategies for patients with low back pain suspected of axSpA. However, there is no agreement on which referral strategy is best. Recently, the Assessment of SpondyloArthritis international Society (ASAS) group has published recommendations for the early referral for suspected axSpA1 (box 1). Nonetheless, some critical remarks can be made regarding these recommendations. Box 1 ### The Assessment of SpondyloArthritis international Society (ASAS)-endorsed recommendations for early referral of patients suspected for having axial spondyloarthritis by primary care physicians or non-rheumatologists1

SAT0275 Assessing the Best Referral Strategy for Axial Spondyloarthritis; Several Referral Strategies Evaluated in Primary Care Patients with Chronic Low Back

Background Several referral strategies for axial spondyloarthritis (axSpA) have been proposed. The goal of these strategies is to overcome the delay between the first symptoms and the final diagnosis of axSpA by supporting primary care physicians in recognizing potential axSpA patients. All referral strategies are tested in their original study population, however no direct comparison of the performance of different strategies in one study population is performed. Objectives To evaluated six different referral strategies for axSpA in unselected young primary care patients with chronic low back pain (CLBP) and secondly to find the optimal referral strategy for daily practice. Methods The referral strategies were evaluated in a large Dutch primary care population of unselected CLBP patients (18-45 years, CLBP ≥3 months, back pain onset <45 years). Patients already diagnosed with ankylosing spondylitis were not invited. Patients underwent a diagnostic work-up including, a standardized history, physical examination, HLA-B27 and CRP testing. A conventional radiograph and MRI of the sacroiliac joints were obtained. Definite axSpA was defined by the ASAS criteria. The following referral strategies were tested, listed by year of publication; the Brandt strategy1, MASTER2, RADAR3, the 2-step strategy4, the CaFaSpA strategy5, and the new ASAS recommendations6. For a description of the different strategies see Figure 1. The performance of the different referral models was assessed by sensitivity, specificity, area under the curve (AUC) and positive predictive value (PPV). Results In total 941 primary care CLBP patients participated (58% female, mean age 36.0 years), of those were 181 (19%) identified as axSpA, 54 of the 181 (30%) were newly diagnosed with ankylosing spondylitis. Almost all referral strategies had a good discriminative performance (AUC >0.7). (Table 1) The MASTER referral strategy had the most balanced sensitivity and specificity. The new ASAS proposal has the lowest AUC, lowest specificity and the lowest PPV.Table 1. Performance of several referral strategies for axial spondyloarthritis tested in primary care patients (18–45 years) with chronic low back pain Strategy AUC (95% CI) Sensitivity Specificity PPV Brandt1 0.80 (0.78–0.82) 1.0 0.60 0.63 Master2 0.88 (0.78–0.91) 0.96 0.82 0.55 RADAR3 0.87 (0.85–0.89) 0.96 0.78 0.51 2-step4 0.64 (0.60–0.68) 0.54 0.75 0.34 CaFaSpA5 0.71 (0.67–0.75) 0.75 0.58 0.30 ASAS recommendation 6 0.61 (0.60–0.63) 1.0 0.22 0.23 Conclusions Almost all referral strategies had a good performance in this primary care cohort of CLBP patients. Strategies including imaging, HLA-B27 and inflammatory back pain (IBP) had the highest AUC and PPV. However imaging and blood tests are not always accessible in primary care, mainly due to high costs. The optimal strategy for primary care should include non-invasive referral parameters without additional costs such as IBP, good response to NSAIDs and family history. References Brandt et al, 2007. Poddubnyy et al, 2011. Sieper et al, 2013. Braun et al, 2013. van Hoeven et al, 2014. Poddubnyy et al, 2014 Acknowledgements An unrestricted research grant was provided by AbbVie. Disclosure of Interest None declared

AB0775 The Diagnostic Value of the Asas Recommendations for Early Referral of Axial Spondyloarthritis in Primary Care Patients with Chronic Low Back Pain: Table 1.

Background There is a delay between the onset of the first back pain symptoms and the final diagnosis of axial spondyloarthritis (axSpA). This delay can be explained by difficulties for primary care physicians to recognize and subsequently refer potential axSpA patients in the huge number of chronic low back pain (CLBP) patients seen in primary care. At this moment there is no widely accepted referral strategy. Recently the ASAS workgroup proposed recommendations for early referral although these were not yet validated in a primary care setting. Objectives To test the ASAS proposed recommendations for early referral in a primary care setting. Methods Our study population included primary care patients (18-45 years) with CLBP (≥3 months, age at back pain onset <45 years) from two Dutch cross-sectional studies. No specific axSpA features were used to include patients. Patients already diagnosed with ankylosing spondylitis were not invited. Patients underwent a diagnostic work-up, including a standardized history, physical examination, HLA-B27 and CRP. A conventional radiograph and MRI of the sacroiliac joints was obtained. Definite axSpA was defined by the ASAS criteria. The ASAS recommendations are applicable in patients with CLBP (≥3 months) and back pain onset before 45 years and should be referred if at least one of the following parameters is present: inflammatory back pain, HLA-B27 positivity, sacroillitis on imaging (X-ray or MRI), peripheral manifestations (arthritis, enthesitis, dactylitis), extra-articulair manifestations (psoriasis, inflammatory bowel disease, uveitis), positive family history for SpA, good response to non-steroidal anti-inflammatory drugs (NSAIDs), elevated acute phase reactants. To test these recommendations, sensitivity, specificity and positive predictive value were calculated. Results In total 941 primary care CLBP patients participated (58% female, mean age 36.0 years), of those were 181 (19%) identified as axSpA, 54 of the 181 (30%) were newly diagnosed with ankylosing spondylitis. 773 (82%) patients had at least one parameter present and thus according to the recommendations should be referred to the rheumatologists. The sensitivity of the ASAS recommendation is 100% (181/181), the specificity 22% (168/760) and the positive predictive value 23% (181/773) (Table 1).Table 1. Patients identified as axSpA vs patients with a positive ASAS referral recommendation (n=941) AxSpA + AxSpA − Total ASAS recommendation + 181 592 773 ASAS recommendation − 0 168 168 Total 181 760 941 Conclusions The ASAS recommendation for early referral has a perfect sensitivity in primary care CLBP population. However this comes at the cost of a low specificity, meaning that almost 80% of the referred patients will undergo unnecessary diagnostic work up. A more specific referral strategy will be needed in daily primary care. Acknowledgements An unrestricted research grant was provided by AbbVie. Disclosure of Interest None declared

SAT0078 The Need to Perform an Impact Study before Using Referral Models for Axial Spondyloarthritis in Daily Practice

Background Unfortunately, only a small part of all published prediction models is used in daily practice, an explanation can be a lack of efficacy or practical feasibility. Therefore prediction modeling research recommends to perform three study phases before using the model in daily practice: (1) developing and internally validating (2) external validation and updating; (3) assessing the models impact on decision making and patient outcomes. Axial spondyloarthritis (axSpA) is characterized by a diagnostic delay, the time between the first symptoms and final diagnosis is on average 7-10 years. This delay requires a prediction model that can early identify possible axSpA patients in the large group of chronic low back pain (CLBP) patients. Objectives To identify all published prediction models (e.g. referral rule or screening methods) for axial spondyloarthritis (axSpA) and to investigate in which prediction modelling phase this model is. Methods Publications describing a prediction model, screening method, or referral rule for axSpA were identified by an Embase and Medline search, at January 29, 2014. After reading all articles we scored which prediction models had been externally validated and whether an impact study had been performed. Results In total 11 studies were identified, all presenting a prediction model for axSpA, applicable in patients with CLBP. Ten studies were developing studies and only one study performed an external validation. So far, none of these studies have performed an impact analysis. Name author Name study Year of publication Country Development Externally validated Impact analysis Brandt (1) 2007 Germany + – – Hermann (2) 2009 Austria + – – Poddubnyy (3) MASTER 2011 Germany + – – Braun (4) 2011 Germany + – – Sieper (5) RADAR 2011 International + – – Hamilton (6) 2012 United Kingdom + – – Juanola (7) RADAR 2013 Spain + – – Braun (8) 2013 Germany + – – van den Berg (9) SPACE 2013 The Netherlands + – – van Hoeven (10+11) CaFaSpA 1+2 2013 The Netherlands + + – Conclusions Of all published prediction models for axSpA only one has been externally validated. Before using any prediction or referral model for axSpA in daily practice, we advise to perform an impact study to investigate the impact of a prediction model on decision making and patient outcomes References Brandt et al. Ann Rheum Dis. 2007. Hermann et al. Rheumatology. 2009. Poddubnyy et al. J Rheumatol. 2011. Braun et al. Ann Rheum Dis. 2011. Sieper et al. Ann Rheum Dis. 2013. Hamilton et al. Rheumatology 2013. Juanola et al. Reumatol Clin. 2013. Braun et al. Rheumatology 2013. van der Berg et al. Rheumatology 2013. van Hoeven et al. Arthritis Care Res. 2013. van Hoeven et al, EULAR 2013 Poster. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.5177

FRI0208 The Impact of A Referral Model for Axial Spondyloarthritis in Young Patients with Chronic Low Back Pain, the Design of an Impact Study

Background Prediction modelling research consists out three major phases, including: (1) developing and internally validating a prediction model; (2) external validation; (3) assessing the models impact on patients outcomes and clinical decision making [1]. Of the few published referral rules (e.g. prediction models) for axial spondyloarthritis (axSpA), only one is recently externally validated in the CaFaSpA 2 study (CAse Finding Axial SPondyloArthritis) [2]. This referral rule has shown to be effective and discriminative in identifying patients with axSpA. Since this referral rule can potentially improve clinical decision making, it is worthwhile to perform an impact analysis to determine its effect in clinical practice. Objectives To evaluate the clinical impact of the CaFaSpA referral rule in young patients with chronic low back pain (CLBP) presenting at the general practioner (GP). Methods The study population are CLBP patients, ages 18-45 years, registered by the ICPC code L03 in the database of their GPs. The design of the study is a stratified prospective cluster randomized trial. The GP practices are the clusters and will be randomized to either a control group wherein usual care according to the Dutch guidelines for low back pain (LBP) will be used, or an intervention group; using the CaFaSpA referral rule. The CaFaSpA referral rule consists out four variables, the ASAS inflammatory back pain questionnaire, a family history for spondyloarthritis, reaction to NSAIDs and LBP duration ≥5 years. If at least two of these four variables are present, the risk of axSpA is increased and referral to the rheumatologist is advised. All patients will be asked to fill in several questionnaires at different time points, baseline, 4, 12 and 24 months. The questionnaires comprises questions on the degree of back pain, clinical features, quality of life and health care costs, including work productivity. Results The primary clinical outcome is a change in the score of the Roland Morris Disability Questionnaire (RMDQ) at 4 months compared to baseline, between the intervention and the usual care group. Secondary endpoints include, back pain intensity (VAS-pain), health related quality of life (SF-36 and EQ-5D), fear avoidance beliefs (Tampa scale for kinesiofobia and Fear avoidance beliefs questionnaire), levels of anxiety and depression (HADS questionnaire) and the impact on work (iPCQ) and health-care resources use and costs (iMCQ). Finally the percentage of referred patients and final diagnosis of axSpA will be investigated. The sample size had been estimated to 834 patients, taking into account lost to follow up and the design effect of a cluster randomized trial. After approval from the Medical Ethical Committee, it is expected that the IMPACT study will start at April 2014. Conclusions If the final goal of a prediction model is to be incorporated into the daily practice, an impact study is inevitable. Therefore we want to perform the IMPACT study to investigate the clinical impact of the CaFaSpA referral rule in young primary care patients with CLBP. References Moons K.G. et al. Heart. 2012. van Hoeven L., et al. EULAR 2013 poster. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.4179

FRI0470 Modification of ‘the asas modification of the berlin algorithm’ in patients with chronic low back pain can be useful for primary care

Background Recently the ASAS modification of the Berlin algorithm (ASAS algorithm) for diagnosing axial spondyloarthritis (aSpA) was published1. The entry criterion, chronic low back pain (CLBP), started before the age of 45, implies that all young patients with CLBP can be referred to the rheumatologist for further diagnostic work-up. Since CLBP is one of the most frequent complaints in primary care, referring all these patients is unfeasible due to high cost. Objectives To assess the performance of the ASAS modification of the Berlin algorithm in an unselected CLBP population; the CAFASPA cohort. To assess whether incorporating the referral model of the CaFaSpA study in the ASAS algorithm, has added value for primary care2. Methods Patients (18-45 yrs) with CLBP were identified from GP records by the ICPC code L03. Assessments included questionnaires, history, physical examination, HLA-B27, CRP, X-ray and MRI. ASpA was defined by the ASAS criteria. A modification was assessed by incorporating the CaFaSpA referral rule in the ASAS algorithm. Descriptive statistics were used to determine the performance both the ASAS algorithm and the CaFaSpA modification of the ASAS algorithm. Results 364 patients participated in the CaFaSpA study. In total 86 (23%) were classified as aSpA. The performance of the ASAS algorithm was 73.2% (n=30) for the X-ray arm, 40.0% (n=12) for the arm having ≥4 SpA features or 2-3 features plus HLA-B27 and 100.0% (n=3) for having 0-1 features plus HLA-B27 and a positive MRI. The data of the CaFaSpA modification were respectively, 100.0%, 60.0% and 100.0% (Fig. 1). Image/graph Conclusions The ASAS algorithm, assessed in secondary care, can not be applied in an unselected CLBP population. Adding the CaFaSpA referral model improves the performance of the ASAS algorithm substantial, leading to useful and more cost-effective model, for daily practice in both primary and secondary care. References vd Berg et al. Annals of the Rheumatic diseases, 2012. v Hoeven et al. Arthritis and Rheumatism 2010 Disclosure of Interest L. Van Hoeven: None Declared, J. Luime: None Declared, M. Hazes: None Declared, A. Weel Grant/research support from: Unrestricted grand from Abbott