Remission has become an accepted goal in the management of rheumatoid arthritis, but its definition remains in flux.
About a year ago, a panel assembled jointly by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) published two provisional definitions of remission in rheumatoid arthritis (RA) for clinical trials: a Simplified Disease Activity Index (SDAI) score of 3.3 or less; or no more than 1 tender and 1 swollen on a 28-joint examination, a C reactive protein (CRP) level of 1 mg/dL or less, and a patient global assessment score of 1 or less on a 0-10 scale (Arthritis Rheum. 2011;63:573-86; Ann. Rheum. Dis. 2011;70:404-13).
The ACR/EULAR panel explicitly said that their definitions of remission were intended for use only in clinical trials for the time being, and the group did not yet endorse their use in routine clinical practice, in part because the definitions had not yet been tested in that setting, and in part because in clinical practice data on acute phase reactants, such as CRP, "are frequently not immediately available."
Dr. David T. Felson, professor of medicine and epidemiology at Boston University as well as first author on the ACR/EULAR remission paper, noted in an interview that "We studied data from clinical trials to develop these remission criteria, and trial patients are not generalizable to those in practice, nor are their assessments as comprehensive."
But even with the new definitions not formally designed for routine practice, their designation by a combined ACR and EULAR panel appears to have helped solidify remission as the benchmark goal for management of most RA patients, capping a decade-long trend. It’s already well accepted that remission is achievable in "at least half" of patients with new-onset RA, noted Dr. James R. O’Dell and Dr. Ted R. Mikuls in an editorial that accompanied the publication of the provisional definition (Arthritis Rheum. 2011;63:587-9). The remission rate in patients with long-standing RA is much lower, more on the order of perhaps 10%, Dr. O’Dell said in an interview.
Noted Dr. Daniel E. Furst: "When I started working on rheumatoid arthritis, we used the word remission with the hope that some day it would be possible. Because of advances in treatment, over the last 10 years it has become possible, and consequently it is totally appropriate that we aim for remission."
The provisional definitions that the panel set for clinical trials serve as "a reasonable set of criteria" for routine practice, said Dr. Furst, who is Carl M. Pearson professor in rheumatology at the University of California, Los Angeles and a member of the ACR/EULAR panel.
"I do this all the time. It requires physicians to routinely quantify patient responses, which is not common right now, but it will become more common. The need for a lab test [measurement of CRP] as part of the definition makes it a little more difficult to use because it usually takes some time to get the blood-test result. What I do is a CDAI [Clinical Disease Activity Index, the sum of tender and swollen joint counts, and physician and patient global assessments] at the same time that I’m obtaining the other results that take time. That’s more practical to do in everyday practice," he said in an interview.
"Right now, my associates and I generally use a DAS28, but we’re rethinking that," in part prompted by the new remission definitions, said Dr. O’Dell, who is Larson professor of medicine and chief of rheumatology at the University of Nebraska in Omaha. "DAS28 is an imperfect measure. I can have a patient with a very low [ESR] of 2 [mm/hr] and their DAS28 will look pretty good until they have three or four swollen joints. But the flip side is I can have a patient who is doing terrific, with no swollen joints, and their [ESR] is 25. Since the ARC/EULAR definition, we have thought about whether we should do more CDAI or SDAI. [ESR] and CRP give information in a different way than what we get from joints, but they often aren’t available in real time.
"The ACR Quality Measures Committee will issue a white paper in late spring on the disease activity measures that it thinks are feasible and that clinicians can use, including the CADI, SDAI, DAS28, RAPID3 [Routine Assessment of Patient Index Data 3], and PAS [Patient Activity Score]. It’s far more important that physicians measure a patient’s disease activity with some scale than which scale you use," he said in an interview. "If you don’t want to do 28-joint counts, then do a RAPID3. The ACR/EULAR panel set its remission criteria for trials, but for routine practice there should be more flexibility" for physicians to use the scale that best fits their approach to practice, Dr. O’Dell said. "The RAPID3 is much easier to do and is available in real time, and is very good. It’s not quite as good as some others, but if that’s what you use, you’ll do fine."