Patients with rheumatoid arthritis who are being treated with methotrexate and who experience persistently elevated levels of acute phase reactants and high swollen joint counts are likely to have later radiographic progression, Dr. Michael E. Weinblatt reported at the annual meeting of the American College of Rheumatology.
This observation emerged from an analysis of data from the methotrexate arms of two earlier clinical trials. Early Rheumatoid Arthritis (ERA) was a trial comparing methotrexate alone versus etanercept alone, while Trial of Etanercept and Methotrexate with radiographic Patient Outcomes (TEMPO) compared monotherapy with these two drugs versus a combination of both. TEMPO also included an early RA subset.
The current study categorized patients according to whether they showed evidence of radiographic progression at week 52, and used logistic regression analysis to evaluate the significance of individual variables measured at week 12 in predicting progression, according to Dr. Weinblatt, associate director, Center for Arthritis and Joint Diseases, Brigham and Women's Hospital, Boston.
The analysis found that a C-reactive protein (CRP) level of 2 mg/dL after 12 weeks of treatment was associated with an increased likelihood of radiographic progression of 29%–44%, compared with a CRP of 1 mg/dL at that time point.
An erythrocyte sedimentation rate (ESR) at week 12 of 20 mm/hr was associated with an increased risk for radiographic progression of 21%–38%, compared with an ESR of 10 mm/hr. And a swollen joint count of 10 at week 12 increased the risk of progression by 18%–76%, compared with a swollen joint count of 5, Dr. Weinblatt wrote in a poster session. Other clinical outcomes at week 12, such as tender joint count and health assessment questionnaire scores, were not significantly different between progressors and nonprogressors among patients in ERA, TEMPO, and TEMPO-Early RA.
The findings from this study support the feasibility of identifying a subset of patients on methotrexate who may be at increased risk of long-term radiographic progression.
Because radiographic progression is associated with long-term disability, the ability to predict which patients are at risk may allow earlier initiation of more aggressive therapies and allow for better outcomes in these patients, according to Dr. Weinblatt.