Undiagnosed SpA Common in Chiropractor Back Pain Referrals

GHENT, Belgium – Over 10% of patients referred by chiropractors to rheumatology had undiagnosed spondyloarthritis, with axial spondyloarthritis being the most common, according to new data. The U.S. study was aimed at understanding what proportion of back pain patients have undiagnosed spondyloarthritis.

The study also found that the most common cause for which patients see chiropractors is neck/cervical pain.

Dr Atul Deodhar

Atul Deodhar, MD, MRCP, rheumatologist and medical director of rheumatology clinics at Oregon Health & Science University, Portland, was senior author of the poster that was presented at the 13th International Congress of Spondyloarthritides.

“In the U.S., many people with back pain go to chiropractors, but many chiropractors are not aware of axial spondyloarthritis [axSpA] terminology, and very little – if anything – is published in chiropractic literature, ” he said in an interview.

He remarked that the study highlighted the need to develop a better strategy to identify undiagnosed patients, because the yield found in their study was poor (13%). “Patient-reported spondyloarthritis criteria are often poor, and do not match rheumatologist-inquired history,” he noted, adding that, “inflammatory back pain is in fact a poor ‘entry point.’ “

Ulrich Weber, MD, rheumatologist from the Practice Buchsbaum in Schaffhausen, Switzerland, commented on the findings, saying he often receives delayed referrals from chiropractors, so “it would be very useful if patients could be more easily and accurately identifiable via this route, but the problem is chiropractors do not have a specific training to spot spondyloarthritis.”

He added that he welcomed the study but noted, “the criteria used to identify patients in this study are broad and I’d worry that it would inundate our rheumatology practice. There remains a real need for a good method of identifying the patients.”

Referral to Rheumatology

Back pain is highly prevalent in the general population, with a global mean lifetime prevalence of 38.9%. Chiropractors treat many patients with back pain of unknown cause.

“In this study, we wanted to see what percentage of patients in chiropractic practice have undiagnosed axial spondyloarthritis, and what are the common complaints. Our hypothesis was that chiropractors may be missing such patients,” Deodhar explained.

Deodhar and colleagues recruited chiropractors from four different parts of the city of Portland into the study. “We think Portland, Oregon, is a typical U.S. city, and our results could be generalized. However, this is our impression alone,” he remarked.

Adults, under the age of 45 years who attended a participating chiropractic clinics between November 2020 and November 2021 for chronic back pain and without a prior diagnosis of spondyloarthritis were eligible for inclusion.

If the patient reported at least one feature of spondyloarthritis in the screening questionnaire they were referred to a rheumatologist for a diagnostic assessment. This assessment involved taking history by telephone, both laboratory tests and imaging, and the patients were categorized as radiographic axSpA, nonradiographic axSpA, peripheral SpA, or no SpA.

The screening questionnaire included the following examples: If the patient was under 45 years and had chronic pain in back, hip or buttocks, then they were asked for more information including whether their pain was gradual (insidious) in onset; if the pain started before the age of 40; and if the pain improved with physical activities or movements. Use of drugs was investigated including whether the pain improved significantly with NSAIDs and whether the patient has current or past heel pains, particularly when waking up in the morning. They were also asked if they have experienced skin psoriasis. Other questions were asked about the presence of uveitis, iritis, family history of psoriasis, inflammatory bowel disease, or ankylosing spondylitis, and whether the patient had unexplained joint pains plus joint swelling.

Ten Percent of Patients Referred to Rheumatology

A total of 3,103 visits to chiropractor clinics were included, of which 115 patients were referred to a rheumatologist. Eventually, 63 patients were fully assessed by a rheumatologist.

Of those patients who were fully assessed, 12.7% has spondyloarthritis, with one having confirmed radiographic axSpA, five having nonradiographic SpA, and two having peripheral spondyloarthritis or psoriatic arthritis.

Based on the referral questionnaire, all patients reported at least four SpA criteria were met, said Deodhar.

Of those patients diagnosed with SpA, 14% (1) has elevated C-reactive protein (CRP) level, 14% (1) were HLA-B27 positive, and 14% (1) were identified as having both elevated CRP and HLA-B27 positivity. Sacroiliac joint inflammation was found in 14% (1) on MRI and one had sacroiliac joint inflammation according to modified New York criteria. One (14%) had both sacroiliac joint inflammation on MRI and elevated CRP, and 14% (1) had both sacroiliac joint inflammation and was HLA-B27 positive.

The top complaints reported by patients at chiropractor clinics were neck and cervical spine pain/spasm (16.8%); followed by acute low back pain (11.7%); acute upper back (7.1%); and chronic lower back pain (6.9%).

No Patients With More Than 10 SpA Criteria

The performance of an initial diagnostic assessment based on patient reported SpA criteria, as compared with the outcome of the full diagnosis (by a rheumatologist) showed that patients with one to four SpA criteria had a sensitivity of 0.50 (95% confidence interval, 0.15-0.85), and specificity of 0.73 (95% CI, 0.61-0.84). This increased to sensitivity of 0.60 (95% CI, 0.17-1.03), and specificity of 0.61 (95% CI, 0.44-0.77) when six SpA criteria were present.

Deodhar said the results supported a need to further develop the chiropractor’s role in identifying the right patients for referral, and that the study showed that a referral strategy is required to find undiagnosed patients with spondyloarthritis from chiropractic offices. “Chiropractors need education for axSpA, when to suspect, and when to refer,” he asserted. “What referral strategy to use is for debate – the ASAS [Assessment in SpondyloArthritis international Society] strategy is too sensitive and not specific enough.”

Deodhar noted that SPARTAN (Group for Research and Assessment of Psoriasis and Psoriatic Arthritis and the Spondyloarthritis Research & Treatment Network) is working on a referral strategy that is likely to be more specific, and that more data would be forthcoming soon.

Deodhar declared affiliations with multiple companies involved in the field unrelated to the study. Weber declared no relevant disclosures.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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