Although overall estimates of the number of individuals in the United States diagnosed with axial spondyloarthritis (axSpA), a form of inflammatory arthritis that causes long-lasting back pain, range between 1.7 million and 2.7 million, the actual incidence rate may be much higher due to low awareness of the disease and diagnostic delays.

A prospective study by Danve et al investigating the usefulness of a self-referral strategy using a clinical feature-based screening questionnaire for patients with suspected axial spondyloarthritis (axSpA) has found the screening tool to be a feasible approach for the early diagnosis of the condition. The study is published in Rheumatology Advances in Practice.

Study Methodology

The researchers developed an A-tool for patients with chronic back pain (CBP) consisting of a three-question prescreen and an eight-question clinical feature-based screening questionnaire that addressed inflammatory back pain, enthesitis, peripheral arthritis, psoriasis, inflammatory bowel disease, and uveitis, and a family history of spondyloarthritis. The researchers distributed the questionnaire to 100 patients: 39 patients via Facebook and 61 via MyChart.

The enrolled patients underwent a clinical history, physical examination, laboratory tests, including a C-reactive protein blood test and an HLA-B27 antigen test; and X-ray and magnetic resonance imaging scans of the pelvis. The clinician’s judgement was considered the gold standard for diagnosing axSpA.

Results

Of the 100 enrolled patients, 86 completed all of the study procedures. Of those, 29 (34%) were diagnosed with axSpA. Seven patients had ankylosing spondylitis (AS) and 22 had non-radiographic axSpA. The remaining 54 patients were diagnosed as having no axSpA, and three were deemed uncertain.

The researchers found the sensitivity and specificity of the individual A-tool questions for diagnosing axSpA ranged from 0.03 to 0.86 and 0.14 to 0.96, respectively. Positive likelihood ratios (+LR) of the individual items in the A-tool ranged from 0.84 to 1.34. There was low to moderate agreement between the patients’ responses on the online A-tool and the corresponding physician-confirmed responses.

“A tool-based strategy for self-referral of CBP patients is a simple, practical, and feasible approach for early diagnosis of axSpA. We need a larger prospective study to validate our findings,” concluded the study authors.

Key Points

• Lack of rheumatology referral is an important modifiable reason for the delayed diagnosis of axial spondyloarthritis.

• A tool-based self-referral or clinical administered strategy can help improve the early diagnosis of axSpA.