Bridging the Gap Between Symptom Onset and Diagnosis in Axial Spondyloarthritis.

Abstract

To evaluate a stratified screening process for the early identification of axial spondyloarthritis (SpA) with consideration of the following: 1) wait times from primary care to rheumatology screen, 2) incremental precision and accuracy from primary care to rheumatology screening, and 3) diagnostic delay. Adults with low back pain attending primary care at low back pain clinics prospectively underwent a primary standardized clinical screening. Patients with low back pain of >3 months who experienced symptom onset at age <50 years were referred for a comprehensive secondary screening by a physical therapist with advanced rheumatology training. At secondary screening, patients with features of inflammation were classified as being at a low, medium, or high risk for axial SpA versus no risk for axial SpA. Precision and accuracy of this screening strata were measured against a rheumatologist with expertise in axial SpA. Overall, 405 patients underwent primary and secondary screening in the present study. The study cohort had a mean ± SD age of 36.9 ± 9.9 years, and 55% were women. HLA-B27 was present in 14.4% of patients. Median wait time from primary screening to secondary screening was 15 days. Axial SpA risk assignment by rheumatologist was 64.9% for no risk or low risk for axial SpA and 35.1% for medium risk or high risk for axial SpA. The best combination of sensitivity (68%), specificity (90%), positive predictive values (80%), and negative predictive values (84%) was evident in the secondary screening. In this cohort, 15.6% of patients received a final diagnosis of axial SpA. Median low back pain duration from symptom onset to diagnosis was 2 years for nonradiographic axial SpA and 7 years for ankylosing spondylitis. A stratified interprofessional screening process can facilitate rapid diagnosis of persistent low back pain with high precision and accuracy in patients who have axial SpA.