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

Objective: 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.

Methods: 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.

Results: 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.

Conclusion: 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.