Chronic back pain may not be as it seems. Many patients suffer for years before being diagnosed with axial spondyloarthritis.
Chronic back pain patients might wait as long as 10 years from symptom onset to axial spondyloarthritis (SpA) diagnosis. Awareness and use of a relatively simply way to identify these patients could help reduce time to diagnosis of SpA, as well as ankylosing spondylitis (AS), according to a July 2016 study in Arthritis and Rheumatology.
For chronic back pain patients who have had back pain for three months or longer with pain that began when they were younger than 45 years, the presence of one or more of three features can help to effectively identify axial SpA. These three features, according to the study, are human leukocyte antigen (HLA) B27 positivity, current inflammatory back pain and MRI or radiographic evidence of sacroiliitis.
Sixty-eight rheumatology sites in the United States participated in the study, which enrolled 751 patients. Forty percent of the patients were new referrals to those practices, 14 percent were self-referrals and 46 percent were existing patients. None had been diagnosed with SpA of any type prior to the study.
These patients had chronic back pain for three or more months, beginning when they were younger than 45 years of age, and they had one or more of the three SpA features.
In the single-visit, non-drug study, researchers report that among the 697 patients with available data, 319, or 46 percent, were diagnosed with axial SpA. Nearly 350 of 744 (47%) fulfilled the Assessment of SpondyloArthritis international Society (ASAS) criteria. Among those, 238 diagnosed with non-radiographic axial SpA and 108 with AS (two had missing data). ASAS criteria specificity was 79 percent and sensitivity was 81 percent.
While the epidemiological information on axial SpA in the U.S. is limited, primarily because of the focus on ankylosing spondylitis, data from the recent National Health and Nutrition Examination Survey suggests axial SpA prevalence in the U.S. is 0.9 to 1.4 percent. This study’s finding that 46 percent of patients enrolled received a diagnosis of axial SpA is in line with two prior studies looking at the simple referral strategy.
With published reports suggesting long delays in diagnosis (patients in this study had an average 14 year delay for AS and non-radiographic axial SpA subgroups), there is a need to improve ankylosing spondylitis and axial SpA identification and diagnosis in the rheumatology setting and among patients newly referred to rheumatologists’ offices, according to the authors.
The study’s sponsor AbbVie was heavily involved in this research. AbbVie contributed to the study’s design, participated in data collection, analysis and interpretation, as well as in the writing, review and approval of the final manuscript. Even publication of the article was contingent on AbbVie’s approval.
“Axial spondyloarthritis (SpA) is a chronic inflammatory disease that primarily affects the sacroiliac joints and spine but can also involve entheses and peripheral joints. It encompasses both ankylosing spondylitis (AS) and nonradiographic axial SpA, which are differentiated based upon the presence or absence of radiographic sacroiliitis, respectively, fulfilling the 1984 modified New York criteria for AS. Both AS and nonradiographic axial SpA typically go diagnosed for many years; however, although AS and nonradiographic axial SpA have comparable clinical manifestations, AS is more easily identified by the presence of sacroiliitis on radiographs. Nonradiographic axial SpA may affect as many women as men, whereas AS more often affects men, which also contributes to a delay in diagnosis in women who have axial SpA.”
- Arthritis and Rheumatology. July 2016. DOI: 10.1002/art.39612.
Deodhar A, Mease PJ, Reveille JD, Curtis JR, Chen S, Malhotra K, Pangan AL. “Frequency of Axial Spondyloarthritis Diagnosis Among Patients Seen by US Rheumatologists for Evaluation of Chronic Back Pain,” Arthritis and Rheumatology. July 2016. DOI: 10.1002/art.39612.