Diagnosing Chronic Back Pain in Psoriasis, Uveitis, Colitis

TOPLINE: 

Patients with psoriasis, uveitis, or colitis who present with undiagnosed chronic back pain should be referred to a rheumatologist for the assessment of axial spondyloarthritis (axSpA), with MRI being a more accurate diagnostic method than clinical features.

METHODOLOGY:

• Researchers assessed the prevalence of axSpA according to the extra-articular presentation and human leukocyte antigen B27 (HLA-B27) status in two Canadian cohorts (SASPIC 1 and 2).
• Overall, 363 adult patients aged ≤ 45 years with psoriasis, uveitis, or colitis who presented with chronic undiagnosed back and/or buttock pain lasting 3 months or more were included.
• Participants were referred to rheumatologists with expertise in axSpA for structured diagnostic evaluations, including history, physical exam, levels of C-reactive protein, HLA-B27 status, and imaging studies.
• An MRI of the sacroiliac joints was conducted in all patients in the SASPIC-2 cohort and in 62.3% of those in the SASPIC-1 cohort.
• The primary outcome was the proportion of patients diagnosed with axSpA after final global evaluation, and the secondary outcome was the impact of MRI on diagnosis and classification.

TAKEAWAY:

• AxSpA diagnoses were made in 46.7% with psoriasis, 61.6% with uveitis, and 46.8% with colitis in the SASPIC-1 cohort and in 23.5%, 57.9%, and 23.3%, respectively, in the SASPIC-2 cohort.
• Being positive for HLA-B27 was linked to the presence of axSpA in 56%-88% of those in both the cohorts.
• Musculoskeletal clinical features were not helpful in differentiating between patients with and without axSpA.
• In both the cohorts, the MRI of the sacroiliac joints was indicative of axSpA in a significantly greater number of patients with psoriasis, uveitis, or colitis who were diagnosed with axSpA than in those not diagnosed with axSpA (P < .05 for all).

IN PRACTICE:

“Our data supports the benefit of recent referral recommendations that advocate referral to a rheumatologist of patients with chronic back pain and extra-articular features related to axSpA,” the authors wrote.

SOURCE:

The study was led by Walter P. Maksymowych, MB ChB, University of Alberta, Edmonton, Alberta, Canada. It was published online in Arthritis & Rheumatology.

LIMITATIONS: 

MRI readers had to rely on their own expertise to decide if an MRI was indeed positive and thus indicative of axSpA. This study included only patients with undiagnosed back pain, and a longer follow-up duration could have led to a higher number of patients being diagnosed with axial inflammation. In SASPIC-1, local rheumatologists conducted MRI evaluations of the spinal lesions only when necessary, while in SASPIC-2, MRI of only the sacroiliac joints was required.

DISCLOSURES:

SASPIC-1 was supported by AbbVie Canada and Janssen Canada, and SASPIC-2 was supported by AbbVie Canada. The authors disclosed receiving grants, consulting fees, speaking fees, and/or honoraria and having other ties with AbbVie and several other pharmaceutical companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.