Identifying patients with axial spondyloarthritis in primary care: how useful are items indicative of inflammatory back pain?
- 1Rheumazentrum Ruhrgebiet, Herne, Germany
- 2Klinik und Poliklinik für Orthopädie, Asklepios Klinikum, Bad Abbach, Germany
- 3Institut für angewandte Statistik, Dr. Jörg Schnitker GmbH, Bielefeld, Germany
- Correspondence to Professor J Braun, Rheumazentrum Ruhrgebiet, Landgrafenstr.15, 44652 Herne, Germany;
- Accepted 11 June 2011
- Published Online First 5 August 2011
Background The value of clinical items defining inflammatory back pain to identify patients with axial spondyloarthritis (SpA) in primary care is unclear.
Objective To identify predictive clinical parameters for a diagnosis of axial SpA in patients with chronic back pain presenting in primary care.
Methods Consecutive 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.
Results The 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.
Conclusion This 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.
Funding The study was sponsored by an unrestricted grant from Abbott, Germany. The company had no influence on the study design, results and analyses.
Competing interests None.
Ethics approval Approval of the ethical committee of the Aerztekammer Westfalen-Lippe at the University of Muenster was obtained and patients gave written informed consent before inclusion in the study.
Provenance and peer review Not commissioned; externally peer reviewed.
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