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.