U.S. experts share concern about how widely the criteria will be applied by other rheumatologists and, perhaps more importantly, by U.S. primary care physicians who see the bulk of these patients initially. “There clearly is a difference of opinion [in the United States and in Europe],” said Dr. Flynn. “I was amazed when I looked at the centers” that participated in the ASAS study. None was in the United States.
The validation study used patients from 25 centers in 16 countries, with 14 of the centers in Europe, 5 in Asia, 4 in Turkey, 1 in Canada, and 1 in Columbia (Ann. Rheum. Dis. 2009;68:777–83).
One possible reason why European rheumatologists have been more active in developing the new criteria is that their population contains a higher proportion of people with the HLA B27 genotype, who are most susceptible to developing axial SpA. “The question is, Are the Europeans not only seeing more, but do they see different patients?” Dr. Flynn noted. “I think you've got to validate [the new criteria] with U.S. patients too.”
“American rheumatologists are still not as well versed in spondyloarthritis as our European colleagues,” Dr. Khan said. But if the new classification criteria were followed, it would result in better patient care, Dr. Reveille said.
Treatment today for axial SpA starts with an NSAID, followed by a course with a second NSAID of a different type if the first fails. If both NSAID regimens fail to produce satisfactory results within 3 months, current standards say the next step is treatment with a TNF inhibitor.
In the United States, those include adalimumab (Humira), etanercept (Enbrel), infliximab (Remicade), and golimumab (Simponi). Although none has Food and Drug Administration approval for use in axial SpA, all four are approved for treating ankylosing spondylitis.
Ideal treatments for axial SpA don't include nonbiological disease-modifying drugs, such as methotrexate and sulfasalazine.
No study results have yet documented that early treatment with an NSAID or with a TNF inhibitor slows or stops progression of axial SpA, but specialists are optimistic that such is the case, and that these data will eventually exist.
“We suspect early treatment might have better outcomes; there is the precedent with rheumatoid arthritis,” Dr. Khan said.
In addition, even without evidence of slowed progression, early treatment “clearly improves quality of life and function and reduces time lost from work,” Dr. Flynn said.
The importance of early identification and treatment of spondylitis has been recognized by the leadership of the Spondylitis Association of America (SAA). Researchers working with SAA sponsorship developed a screening tool aimed at helping people with chronic back pain self-identify whether they have indications of an inflammatory process that needs medical evaluation.
A report on the development of the SAA screening tool for ankylosing spondylitis is scheduled to appear in the January issue of Arthritis Care and Research, and then the SAA will publicize it as an Internet-based tool, said SAA executive director Laurie Savage.
Patients with back pain for at least 3 months and with an age of onset younger than 45 years are classified as having spondyloarthritis if they have sacroiliitis on imaging plus at least one spondyloarthritis feature (see below), or if they are HLA B27 positive and have at least two other spondyloarthritis features.
Sacroiliitis on imaging is defined as one of the following:
▸ Active acute inflammation on MRI highly suggestive of sacroiliitis associated with spondyloarthritis.
▸ Definite radiographic sacroiliitis, according to the modified New York criteria.
Spondyloarthritis features include the following:
▸ Inflammatory back pain
▸ Arthritis
▸ Enthesitis
▸ Uveitis
▸ Dactylitis
▸ Psoriasis
▸ Crohn's disease/ulcerative colitis
▸ Good response to NSAIDs
▸ Family history for spondyloarthritis
▸ HLA B27 positive
▸ Elevated C-reactive protein (in the context of chronic back pain)
In these MRI images of a patient with spondyloarthritis, black arrowheads show erosions, a black arrow indicates accentuated sclerosis, white arrows show active osteitis, and white arrowheads show active enthesitis.
Source ©Elsevier, European Journal of Radiology, Mager et al, 71, 2, Elsevier Ireland Ltd, 182–8, 2009