WASHINGTON, D.C.—The methods used to classify ankylosing spondylitis (AS) have changed dramatically in recent years, giving rise to a more nuanced view of the disease—a valuable clinical tool and a benefit to the patient, an expert said here at the 2012 ACR/ARHP Annual Meeting, held November 9–14 in Washington, D.C. [Editor’s Note: This session was recorded and is available via ACR SessionSelect at www.rheumatology.org.]
Désirée van der Heijde, MD, PhD, professor of rheumatology at Leiden University in the Netherlands, reviewed the new Assessment of SpondyloArthritis International Society (ASAS) classification criteria for axial spondylarthritis (SpA), which expanded the lens through which the disease is seen.1 Dr. Van der Heijde also offered her thoughts on the best current treatment for AS, which continues to rely heavily on a combination of nonpharmacological and pharmacological (nonsteroidal antiinflammatory drugs [NSAIDs] and tumor necrosis factor [TNF] inhibitors) treatment.
Researchers are hoping for a way to identify AS patients earlier; on average, nine years pass from the time the first symptoms are felt to the time of diagnosis.
New Tools for Early Identification
When it comes to identifying AS, until 2009, the focus was mainly on the modified New York criteria. “When we used the modified New York criteria, we can only try to treat these patients when they have sacroilitis on the radiographs,” Dr. van der Heijde said. “But that’s not the way it starts. It starts earlier with back pain.”
Spondylarthritis is now subgrouped as either predominantly axial SpA or predominantly peripheral SpA—ankylosing spondylitis falls into the axial group.
With the ASAS criteria, there is less reliance on radiographic findings. When it comes to axial SpA, classification can be made if there is sacroiliitis on imaging along with at least one SpA feature—the list includes inflammatory back pain, arthritis, enthesitis in the heel, uveitis, dactylitis, psoriasis, Crohn’s disease, good response to NSAIDs, a family history for SpA, the presence of the HLA-B27 gene that has been linked to AS, and elevated C-reactive protein (CRP) levels. But a condition also qualifies as axial SpA if the HLA-B27 gene is present, along with at least two of those SpA features.1
The shift away from relying so heavily on radiographic findings has led to more women being categorized as having axial SpA. Going by the patients participating in clinical trials, only about 25% of patients categorized using the modified New York criteria were women. But it’s now been found that, among those with nonradiographic axial SpA, 50% are women, Dr. van der Heijde said.
The ASAS axial SpA criteria have been found to be reliable, with an 82.9% sensitivity rate and an 84.4% specificity rate. That high specificity greatly outpaces past criteria.2
The ASAS classification criteria, she cautioned, were not expressly developed for diagnosis.
Treatment
Home exercise can work well as a nonpharmacological treatment, Dr. van der Heijde said, but she noted that water-based therapy and supervised physical therapy are more effective. As for drug treatment, Dr. van der Heijde said, “NSAIDs are still the cornerstone of the drug treatment for patient with ankylosing spondylitis.”3
Other than that, the only other option is TNF bockers. When NSAIDs fail in AS patients, doctors can go straight to those, she said. That’s a difference from predominantly peripheral SpA, for which there are data showing that sulfasalazine and local corticosteroids also might be helpful. For AS, analgesics are probably not a good option, Dr. van der Heijde said. “There is, in fact, very little evidence that analgesics are also efficacious in patients with ankylosing spondylitis.”3
Which NSAID is best for treating pain in AS? There is scant evidence that any one of them is better than the others. A German study comparing five types found little difference in treatment for pain.4 The evidence is solid, though, that continuous use of NSAIDs works better than on-demand use when it comes to slowing radiographic progression of the disease, she said.5 And there is even greater benefit from continuous use over on-demand use in patients with elevated CRP levels.6 The data also show that there is a clear benefit, in terms of radiographic progression, to getting a higher dose of an NSAID if the patient has syndesmophytes and elevated CRP levels.7 “But in patients with no syndesmophytes and normal CRP, there’s no difference,” Dr. van der Heijde said.
When NSAIDs fail, TNF blockers are the next step for AS patients. But when to switch? The “2010 update of the international ASAS recommendations for the use of anti-TNF agents in patients with axial spondyloarthritis” offers guidance.8 It suggests that switching is appropriate when two NSAIDs fail over four weeks. More could be tried, but two is enough, especially in cases of patients with active disease. Also, patients being moved to a TNF blocker should have high disease activity—a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score of 4 or higher. In addition, the rheumatologist should be convinced there is active disease calling for the start of a TNF blocker.
Patients on TNF blockers should be assessed after at least 12 weeks of treatment. Discontinuation should be considered if there is not a BASDAI improvement of 50% or more or an absolute improvement of two units on the BASDAI, plus a positive expert opinion. “All the TNF blockers seem to be similarly efficacious for musculoskeletal manifestations,” Dr. van der Heijde said. “[It is] only if you have extraarticular manifestations such as IBD [inflammatory bowel disease] that it’s important to select your TNF blocker.”
Thomas Collins is a freelance medical writer based in Florida.
References
- Rudwaleit M, van der Heijde D, Landewé R, et al. The development of Assessment of SpondyloArthritis International Society classification criteria for axial spondyloarthritis (part II): Validation and final selection. Ann Rheum Dis. 2009;68:777-783.
- Rudwaleit M, van der Heijde D, Landewé R, et al. The Assessment of SpondyloArthritis International Society classification criteria for peripheral spondyloarthritis and for spondyloarthritis in general. Ann Rheum Dis. 2011;70:25-31.
- Braun J, van den Berg R, Baraliakos X, et al. 2010 update of the ASAS/EULAR recommendations for the management of ankylosing spondylitis. Ann Rheum Dis. 2011;70:896-904.
- Zochling J, Bohl-Bühler MH, Baraliakos X, Feldtkeller E, Braun J. Nonsteroidal anti-inflammatory drug use in ankylosing spondylitis—a population-based survey. Clin Rheumatol. 2006;25:794-800.
- Wanders A, Heijde D, Landewé R, et al. Nonsteroidal antiinflammatory drugs reduce radiographic progression in patients with ankylosing spondylitis: A randomized clinical trial. Arthritis Rheum. 2005;52:1756-1765.
- Kroon F, Landewé R, Dougados M, van der Heijde D. Continuous NSAID use reverts the effects of inflammation on radiographic progression in patients with ankylosing spondylitis. Ann Rheum Dis. 2012;71:1623-1629.
- Poddubnyy D, Rudwaleit M, Haibel H, et al. Effect of non-steroidal anti-inflammatory drugs on radiographic spinal progression in patients with axial spondyloarthritis: Results from the German Spondyloarthritis Inception Cohort. Ann Rheum Dis. 2012;71:1616-1622.
- van der Heijde D, Sieper J, Maksymowych WP, et al. 2010 Update of the international ASAS recommendations for the use of anti-TNF agents in patients with axial spondyloarthritis. Ann Rheum Dis. 2011;70:905-908.