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OBJECTIVE: Chronic inflammatory back pain (IBP) is frequently reported in axial SpA (axSpA) but also in the general population. We evaluated a recently proposed two-step referral system for early recognition of axSpA in primary care and compare it with other combinations of symptoms and SpA-related items. METHODS: Consecutive chronic back pain patients ≤45 years of age answered a questionnaire and were seen by a primary care physician who decided whether HLA-B27 needed to be determined. They were then referred to a rheumatologist who made the diagnosis. Generally sticking to the two-step system with HLA-B27 as an additional option, combinations with a sensitivity ≥90% and a likelihood ratio >4 were compared. RESULTS: A total of 326 patients were included, 46 of whom were diagnosed with axSpA (14.1%). The sensitivity of the strategy was 87%, the specificity was 56.8% and the positive and negative predictive values were 24.8% and 96.4%, respectively. A 'good response to NSAIDs', 'morning stiffness >30 min' and 'elevated C-reactive protein' performed best, with a sensitivity of 91%, specificity of 67%, positive predictive value of 31% and negative predictive value of 98%. On that basis, only three patients had to be seen by a rheumatologist to diagnose one. CONCLUSION: The earlier proposed referral system worked well but was outperformed by other combinations with high sensitivity and better specificity, which deserve to be prospectively studied.
Baraliakos et al. (Thu,) studied this question.