ACR Convergence 2021—Alexis Ogdie, MD, associate professor of medicine and epidemiology at the University of Pennsylvania, Philadelphia, presented key principles of diagnosis and management of spondyloarthritides at the ACR Convergence session CARE: Spondyloarthritis.
Psoriatic Arthritis
Dr. Alexis Ogdie
Dr. Ogdie began her presentation with an overview of the treat-to-target approach to psoriatic arthritis (PsA). She described the primary target as remission and the alternate target as low disease activity. The treat-to-target approach requires that rheumatologists objectively monitor disease, modify treatment to get to target and follow up on any changes in disease activity the patient experiences. This process should be guided by the 2018 ACR/National Psoriasis Foundation Guideline for the Treatment for Psoriatic Arthritis.1
Although the guideline states that the treat-to-target recommendation for patients with active PsA is conditional based on low-quality evidence, it nevertheless recommends following a treat-to-target strategy for most patients. The guideline does acknowledge, however, that such a strategy may not be appropriate for patients due to the risk of increased adverse events, costs of therapy and the burden imposed by medications and additional visits associated with tighter control.
The guideline recommends that the Disease Activity in Psoriatic Arthritis (DAPSA) or Minimal Disease Activity (MDA) score be used to assess treatment response. DAPSA includes a 68 tender joint count, 66 swollen joint count, patient global assessment of 0–10, patient pain of 0–10 and C-reactive protein (CRP) in mg/dL.
Dr. Ogdie pointed out that if the MDA is used to assess disease activity in patients with PsA, it should include assessment of swollen joints, tender joints, enthesitis, the Health Assessment Questionnaire (HAQ), patient global assessment, patient pain and psoriasis. A paper published after the guideline was released indicated that the Psoriatic Arthritis Impact of Disease (PsAID) questionnaire may be able to replace the HAQ, and, according to Dr. Ogdie, the PsAID is increasingly used by rheumatologists in Europe.2
The 2018 guideline also specifies that, in most cases, a treatment-naive patient with PsA should be prescribed tumor necrosis factor (TNF) inhibitors in preference to oral, small-molecule drugs. Other therapies may be used in special conditions (e.g., an interleukin 17 inhibitor in the setting of severe psoriasis).
Prior to treatment, however, it is important to ascertain if the patient has inflammatory bowel disease, said Dr. Ogdie. If the patient does have inflammatory bowel disease, rheumatologists should not prescribe drugs that are incompatible with the condition, and she emphasized the importance of heeding Boxed Warnings.
Dr. Ogdie suggested testing for fecal calprotectin in patients suspected of inflammatory bowel disease and highlighted a 2015 study that included 895 patients with a mean age of 33 years.3 The population comprised patients diagnosed with inflammatory bowel disease (10.2%), another gastrointestinal condition associated with an abnormal gastrointestinal tract (7.3%) and functional gastrointestinal disease (63.2%).
When the investigators applied a threshold of ≥50 µg/g for inflammatory disease vs. functional disease, they calculated a sensitivity of 0.97. However, it is important to note that the threshold had a specificity of only 0.74, for a positive predictive value of 0.37. The negative predictive value was 0.99.
Non-Radiographic Axial Spondyloarthritis
Dr. Ogdie emphasized that although the Assessment of SpondyloArthritis International Society (ASAS) classification criteria for axial spondyloarthritis (axSpA) are not diagnostic criteria, they can be useful in guiding the thought process for diagnosis.4
The criteria state that to classify a patient as having axSpA for research purposes, the patient must have experienced at least three months of back pain and be younger than 45 years old at disease onset. Patients must also have sacroiliitis visible on imaging and at least one spondyloarthritis feature, or HLA-B27 plus at least two spondyloarthritis features, such as inflammatory back pain, arthritis or enthesitis.
Unfortunately, according to Dr. Ogdie, untrained radiologists have poor inter-rater reliability in reading imaging of sacroiliac joints. She suggested that rheumatologists personally examine each scan, and she recommends that rheumatologists review the 2009 ASAS handbook for guidance on reading scans of sacroiliac joints.4
Dr. Ogdie also emphasized, however, the importance of obtaining dedicated sacroiliac joint films. These specific images are important because images of the lumbar spine are unlikely to provide the necessary information about the sacroiliac joint.
Likewise, she explained that it is difficult to assess the sacroiliac joint with a magnetic resonance imaging (MRI) of the lumbar spine and instead an MRI of the pelvis or sacrum is required.
Dr. Ogdie then highlighted the complications that can occur when reading a post-partum MRI of the pelvis. She explained that one study found that at six months post-partum, 15% of women met the ASAS definition of sacroiliitis.5
Thus, she suggested that when rheumatologists read scans of post-partum women they keep in mind that although bone marrow edema may suggest inflammation, it is not specific for axSpA. In contrast, erosion is more specific for axSpA and is much less common than bone marrow edema in post-partum women. Dr. Ogdie concluded that “if you have erosion, you are probably more likely looking at real disease.”
Fibromyalgia can also complicate the diagnosis of axSpA because, according to Dr. Ogdie, some of the symptoms of axSpA can overlap with fibromyalgia. She explained that “if you have pain and you aren’t sleeping well, you are going to have some of the brain fog and cognitive issues. … The challenge is that fibromyalgia commonly coexists with axSpA.”
She concluded by stating that CRP can help distinguish fibromyalgia from axSpA because CRP should not be elevated in patients with fibromyalgia.
Lara C. Pullen, PhD, is a medical writer based in the Chicago area.
References
- Singh JA, Guyatt G, Ogdie A, et al. Special article: 2018 American College of Rheumatology/National Psoriasis Foundation guideline for the treatment of psoriatic arthritis. Arthritis Rheumatol. 2019 Jan;71(1):5–32.
- Johnson K, Ye JY, Chandran V, et al. A novel role for the psoriatic arthritis impact of disease (PsAID) questionnaire. Sem Arth Rheum. 2019 Oct;49(2):241–245.
- Kennedy NA, Clark A, Walkden A, et al. Clinical utility and diagnostic accuracy of faecal calprotectin for IBD at first presentation to gastroenterology services in adults aged 16–50 years. J Crohns Colitis. 2015 Jan;9(1):41–49.
- Sieper J, Rudwaleit M, Baraliakos X, et al. The Assessment of SpondyloArthritis International Society (ASAS) handbook: A guide to assess spondyloarthritis. Ann Rheum Dis. 2009 Jun;68 Supple 2:ii1–44.
- Renson T, Depicker A, De Craemer A-S, et al. High prevalence of spondyloarthritis-like MRI lesions in postpartum women: A prospective analysis in relation to maternal, child and birth characteristics. Ann Rheum Dis. 2020 Jul;79(7):929–934.
