Comparison of 2 referral strategies for the diagnosis of axial spondyloarthritis in Spain. The RADAR study

Objectives: Improving referral of patients with back pain to rheumatologists could accelerate the diagnosis of axial spondyloarthritis. The RADAR study compared two strategies in the referral of patients with chronic back pain (>3 months) with an onset before the age of 45 years from primary care centers to rheumatology departments, in relation to the diagnosis of axial spondyloarthritis.

Patients and methods: Each primary care center was assigned a referral strategy for its patients: (a) strategy 1, patients who had one of the 3 following criteria: inflammatory back pain, HLA-B27 positivity or sacroiliitis in imaging; or (b) strategy 2, patients who had 2 of the following 6: inflammatory back pain, HLA-B27 positivity, sacroiliitis in imaging, family history of axial spondyloarthritis, extra-articular manifestations or good response to nonsteroidal antiinflammatory drugs. The rheumatologist established the final diagnosis.

Results: Eighty-eight Spanish patients (mean age 36.8 years [SD 8.7], 55.7% females and 44.3% males) were referred for evaluation, 60 patients under strategy 1 and 28 under strategy 2. A definitive diagnosis of axial spondyloarthritis was established in 25.4% with strategy 1 and in 28.6% with strategy 2 (p=NS). Inflammatory back pain was the criterion most commonly used for referral, and the agreement rate between the primary care physician and rheumatologist was 75%.

Conclusions: A simple referral strategy based on one of three3 criteria proved as effective as a strategy based on two of 6 criteria in diagnosing axial spondyloarthritis. Inflammatory back pain was the criterion most commonly used for patient referral.