Stratified Screening Process for Early Diagnosis of Low Back Pain in Patients With Axial Spondyloarthritis

Sport injury, Man with back pain
Researchers assessed a screening process for the early identification of axial spondyloarthritis, which may help bridge the gap between low back pain and axSpA diagnosis.

In patients with axial spondyloarthritis (axSpA), the use of a stratified interprofessional screening process can help in the rapid and accurate diagnosis of persistent low back pain (LBP), supporting the early identification of axSpA, according to study results published in Arthritis Care & Research (Hoboken).

Researchers sought to assess the use of a stratified screening process for the early identification of axSpA with regard to wait times from primary care to rheumatology screening; incremental precision and accuracy from primary care to rheumatology screening; and delays in diagnosis.

A prospective, observational study was conducted among patients with LBP who were referred to the Interprofessional Spine Assessment and Education Clinics (ISAEC) program in Ontario, Canada. Patients aged 18 years and older with back-dominant pain were evaluated using ISAEC — a Canadian government-funded interprofessional model for chronic LBP with a network of community primary care and centralized tertiary care providers across Ontario.

Patients referred to the ISAEC program received primary screening for inflammatory back pain (IBP) and an IBP risk score.

Patients who completed the primary screening and fulfilled the minimum IBP criteria were referred for secondary screening by 1 of 2 extended scope practitioners associated with the Spondylitis Program at Toronto Western Hospital. At the secondary screening, patients who had inflammatory features were considered to be at low, medium, high, or no risk for axSpA.

A total of 405 patients with LBP underwent both primary and secondary screening. Mean participant age was 36.9±9.9 years; 55% of the patients were women. Presence of the human leukocyte antigen B27 gene (HLA-B27) was reported in 14.4% of the participants. Median wait time reported from primary screening to secondary screening was 15 days.

According to axSpA assignment by a rheumatologist, 64.9% of the participants had no risk or were at low risk for axSpA, and 35.1% were at medium or high risk for axSpA. Specificity, sensitivity, and positive and negative predictive values were established for the primary and secondary screen, which were based on the clinical judgment of the rheumatologist. Patients with a positive screen were at moderate or high risk for axSpA and those with a negative screen were at low or no risk for axSpA.

The best combination of specificity (90%), sensitivity (68%), and positive (80%) and negative (84%) predictive values was observed with the secondary screen. Overall, 15.6% of participants received a final diagnosis of axSpA. Median duration of LBP from onset to diagnosis was 2 years for nonradiographic axSpA and 7 years for ankylosing spondylitis.

Study limitations included the validity of the model as it pertained to the Canadian health care system; the difference in axSpA risk assessment between the extended scope practitioner and the rheumatologist; and the potential for false negatives.

Researchers concluded, “The results of this study provide a validated model of care to bridge the gap between onset of back pain and axial spondyloarthritis diagnosis, support a potential change in the assessment and management of [axSpA] and may influence similar initiatives within other subsets of inflammatory arthritis.”

Disclosure: Multiple study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures. 


Passalent L, Sundararajan K, Perruccio AV, et al. Bridging the gap between symptom onset and diagnosis in axial spondyloarthritis. Arthritis Care Res (Hoboken). Published online July 15, 2021. doi:10.1002/acr.24751