BERLIN – The 2010 criteria for classifying rheumatoid arthritis accomplish what they were designed to do in patients with early disease: boost the sensitivity for identifying patients who are likely to eventually develop rheumatoid arthritis and could therefore benefit from early treatment.
A comparison of the 2010 criteria (Arthritis Rheum. 2010;62:2569-81) against the 1987 rheumatoid arthritis (RA) classification criteria (Arthritis Rheum.1987;31:315-24) in a cohort of 269 patients with early disease showed that the 2010 method increased the sensitivity for finding patients with early-stage disease who were destined eventually to develop full-blown RA over the next 6 years to 86% sensitivity, compared with 78% sensitivity for the 1987 criteria, a statistically significant difference, Dr. Julia Nicolau said at the annual meeting of the European Congress of Rheumatology.
Dr. Alan J. Silman
Among the 229 patients from this group with no joint erosions detectable at baseline, the 2010 criteria worked even better, primarily because the specificity of the criteria jumped from 59% in the full cohort examined to 71% when patients with one or more joint erosions were excluded. The positive predictive value of the 2010 criteria was 80% for the entire group of 269 (compared with 81% for the 1987 criteria), but in the subgroup without erosions, the positive predictive value of the 2010 criteria was 85%, said Dr. Nicolau, a rheumatologist at Rouen (France) University Hospital.
In addition, in an analysis of the area under the receiver-operator curve the 2010 criteria applied to patients without any erosions at baseline accounted for 82% of the confirmed RA cases after 6 years, significantly more than the 79% of cases identified by the 1987 criteria.
"The mind-set we had when we set up the [2010] criteria was to try to catch everybody [who would soon develop RA], and accept that we might treat some people who we don’t know will develop erosive disease," said Dr. Alan J. Silman, medical director of the U.K. Arthritis Research Campaign and a member of the committee that wrote the 2010 RA classification criteria. "Missing a case of RA is problematic because the interventions we have are fairly effective. Among patients with early arthritis, some will progress to persistent, erosive disease, and the issue is what should we use to identify the patients who should receive intervention" at an early stage. "We may treat some patients who won’t have bad outcomes [and won’t progress to erosive joints], but we accept that we need to treat a lot of patients to prevent the bad outcomes."
The results reported by Dr. Nicolau used the Very Early Arthritis Cohort, which included 269 patients with at least two swollen joints for less than 6 months who appeared to have no other type of arthritis causing their symptoms. The 2010 criteria identified 68% as having RA, while the 1987 criteria identified 59% of these early-stage patients with RA. The researchers had 6-year follow-up data for these patients, which allowed them to compare the results of baseline assessment with each of the two criteria against the eventual, long-term clinical diagnosis of RA.
Dr. Nicolau and her associates also evaluated the 1987 and 2010 criteria using a different end point as the standard for determining which patients eventually developed RA, the number of patients with at least three erosive joints after 2 years of follow-up. Against this standard, the 2010 criteria performed virtually identically as the 1987 criteria. Both criteria identified early-stage RA with 95% sensitivity, and both accounted for 82% of early-stage patients who eventually developed RA 2 years later.
Dr. Nicolau and Dr. Silman said that they had no disclosures. Dr. Silman was a member of the committee that wrote the 2010 rheumatoid arthritis classification criteria.