Major Finding: The proposed ACR/EULAR cut point for “definite RA” may be held at 6, whereas 3 may be an appropriate cut point for “probable RA.”
Data Source: A cohort of 566 patients with early undifferentiated arthritis.
Disclosures: Dr. Visser said that he had no relevant financial disclosures to make.
The revised classification criteria for rheumatoid arthritis that were developed jointly by the American College of Rheumatology and the European League Against Rheumatism are valid to predict future persistent arthritis and joint erosions in patients with early undifferentiated arthritis, judging from results from a large study.
“Methotrexate is the cornerstone of RA management and frequently initiated as the first [disease-modifying antirheumatic drug] if the suspicion for RA is raised,” lead author Dr. Henk Visser said in an interview with Rheumatology News.
“However, the new ACR/EULAR criteria were not validated against what RA is considered to be: persistent and erosive arthritis,” according to Dr. Visser.
For the study, the researchers validated the new ACR/EULAR criteria for their ability to predict persistent and erosive arthritis in an existing early arthritis cohort of 566 patients who were followed for 2 years (Arthritis Rheum. 2002;46:357–65).
They were included in the current study if at baseline they had had arthritis of at least one joint, arthritis that was not explained by another diagnosis, and no joint erosions on x-ray, and if they had also completed 2 years of follow-up.
The data were presented by Jaap Fransen, Ph.D., of St. Radboud University Medical Centre Nijmegen (the Netherlands).
The mean age of patients at baseline was 52 years; 56% were female.
Dr. Visser, a rheumatologist at Rijnstate Hospital in Arnhem, the Netherlands, said in an interview that at 2 years of follow-up, 45% of patients had persistent arthritis, and 48% of them had erosions.
At baseline, patients had a median of two swollen joints, 23% were positive for IgM rheumatoid factor, 18% were positive for anticitrullinated protein antibodies, 25% had symptoms lasting longer than 6 weeks, and the patients' median erythrocyte sedimentation rate was 26 mm/h.
The researchers found that joint involvement, serology, symptoms lasting longer than 6 weeks, and elevated acute phase reactants were significantly associated with persistent arthritis, whereas joint involvement and serology were significantly associated with erosions.
The strength of the 0–10 “risk” score of the revised classification criteria was significantly associated with persistent arthritis (odds ratio, 1.6) and erosions (OR, 1.8), with areas under the ROC curve of .79 and .81, respectively.
Patients with a risk score of 6 or higher at baseline had a .74 probability to develop persistent arthritis at year 2, and given persistence there was a .68 probability to develop erosions. The discriminative ability of the new ACR/EULAR criteria and the earlier prediction model developed for early diagnosis of RA by Dr. Visser and his colleagues are comparable.
The previous ACR classification criteria performed much more poorly.
Dr. Visser and his associates concluded that the proposed cut point for “definite RA” may be held at a risk score of 6, whereas a score of 3 may be an appropriate cut point for “probable RA,” according to Dr. Visser and associates.
Disclosures: Dr. Visser said that he had no relevant financial disclosures to make.
Effusion and bone edema can be seen on this wrist MRI of a patient with rheumatoid arthritis.
Source ©2010 Kevin Shea, M.D/Custom Medical Stock Photo, All Rights Reserved