What is the Best Referral Strategy for Axial Spondyloarthritis? A Prospective Multicenter Study in Patients with Suspicious Chronic Low Back Pain

Objective: To assess the value of referral strategies for axial spondyloarthritis (axSpA) in patients with suspicious chronic inflammatory low back pain (LBP), to estimate the value of inflammatory back pain (IBP) for referral, and to identify the predictive factors of the final diagnosis of axSpA in Middle Eastern Arab countries.

Methods: The study was multicentric, prospective, and conducted in LBP first-line clinics (rheumatology, internal, family medicine, orthopedic surgery, neurosurgery, and neurology). Consecutive adult patients aged under 45years were included in case of LBP suspicious of inflammatory nature according to the first-line physician. The rheumatologist's final diagnosis was the gold standard. The diagnostic properties of ten referral strategies (Brandt I, II, III, Hermann, RADAR, RADAR 2/3, MASTER, Braun, CAFASPA, and ASAS) and of IBP were calculated. A multivariable logistic regression identified the clinical predictive factors of axSpA.

Results: In 515 referred patients, axSpA was confirmed in 48%, refuted in 43%, and diagnosis remained inconclusive in 9%. The optimal referral strategy was the MASTER (PLR 3.3), which comprises IBP, good response to NSAIDs, positive HLA-B27, and SpA family history. Considering strategies without HLA-B27, the RADAR 2/3 had a PLR of 2.9 (IBP, good response to NSAIDs, any extra-musculoskeletal manifestation). The predictive factors for axSpA were MRI sacroiliitis, positive HLA-B27, high CRP, psoriasis, IBP, and longer symptom duration. Of all patients, 35% were self-referred, 16% were referred by primary care physicians, and 15% by neuro/orthopedic surgeons.

Conclusion: Optimizing physicians' awareness of these clinical features may enhance referral in axSpA.