Identification of patients with axial spondylarthritis in primary care (AWARE study)

Abstract

Background: Early detection of patients with axial spondylarthritis (axSpA) in primary care is difficult. The combination of various parameters indicative of inflammatory back pain (AWARE criteria) was found to be beneficial in an initial study. Objective: Review of the criteria for the identification of young patients with axSpA and chronic back pain (≥3 months of back pain). Material and methods: In adult patients with chronic back pain and age at onset of symptoms <45 years, orthopedic surgeons documented various possible axSpA characteristics before referral to the rheumatologist. Results: Overall, the data from 1306 patients were recorded. Of these, ultimately 500 patients were also seen by rheumatologists, 199 patients (39.8%) were diagnosed with axSpA while 301 (60.2%) had non-specific back pain. A total of 87 patients had ankylosing spondylitis (44%) and 112 non-radiographic axSpA (56%). The ASAS classification criteria were fulfilled by 226 patients (45.2%). The mean age of axSpA patients was 38 years, 56% were male with a mean duration of back pain of 98 months. The AWARE criteria had a sensitivity and specificity of 69.3% and 40.3% (n = 343), respectively, when ≥4/5 criteria were chosen. Positive imaging for sacroiliitis using magnetic resonance imaging (MRI) or X‑ray was present in 77% of patients and positive HLA-B27 was identified in 59% of axSpA patients. The combination of positive imaging and HLA-B27 had the highest likelihood ratio for diagnosis of axSpA. Conclusion: Although the study design used here led to a preselection and thus to a bias in the statistical evaluation, the study confirmed the benefit of the AWARE criteria for the early detection of patients with axSpA. In further studies, the 2‑stage approach with initially 3 clinical questions and then an optional HLA-B27 test is currently being investigated further.