Diagnostic accuracy of recently proposed criteria for inflammatory back pain (IBP) in suspected ankylosing spondylitis (AS) and early axial spondyloarthritis (axial SpA)

• Applicant: Professor Dr. Joachim Sieper, since 2/2010
• Subject Area: Rheumatology
• Term: from 2008 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 44171605

Making a diagnosis of ankylosing spondylitis (AS) is delayed on average by 5-10 years. Chronic back pain is the leading symptom in AS and usually the first symptom leading to medical consultation. The back pain as a clinical symptom in AS has specific characteristics which are referred to as inflammatory back pain (IBP). We recently found in patients with established AS that four IBP parameters differentiated best between AS and patients with non-inflammatory causes of chronic back pain. These were i) morning stiffness ≥ 30 minutes, ii) improvement with exercise, not with rest, iii) awakening at the early morning hours/ 2nd half of the night, and iv) alternating buttock pain. The presence of at least 2 out of 4 parameters resulted in a sensitivity of 70%, specificity of 81%, and a positive likelihood ratio (LR+) of 3.7 (LR+ 12.4 if 3 of 4 parameters were present). The diagnostic accuracy of IBP in patients with suspected, yet undiag-nosed AS/ axial SpA referred to a rheumatologist is less clear as is the accuracy of IBP assessment by less experienced physicians, and the self-assessment of IBP by the patient. This study aims to evaluate the diagnostic accuracy of IBP criteria by blind assessment of IBP by independent rheumatologists (n=6) in 400 patients with suspected AS referred to rheumatology practices (n=4) or hospitals (n=2). In addition, the concordance rate of IBP if assessed by primary care physicians/ orthopaedists (n=15-20) and self-assessed by the patient as compared to experienced rheumatologists will be evaluated in 150 patients.

• DFG Programme: Clinical Trials
• Ehemaliger Antragsteller: Privatdozent Dr. Martin Rudwaleit, until 2/2010