Likelihood of remaining erosion-free difficult to predict in RA patients
MedWire News: US clinicians have highlighted the difficulty in predicting which rheumatoid arthritis (RA) patients will remain free from bone erosion, a key indicator of a positive prognosis.
Previously, research has focused on identifying patients at risk for bone erosion as these individuals are expected to benefit most from early aggressive treatment.
However, some RA patients never progress to joint damage and identifying these individuals could allow use of less potent therapies, explain Katherine Liao and co-workers, from Brigham and Women's Hospital in Boston, Massachusetts.
To investigate, the team followed-up 271 RA patients with disease duration of no longer than 10 years who had bilateral hand radiographs at study baseline and again 2 years later. The patients were assessed for joint erosion using the Sharp/van der Heijde scores.
Data were collated on a range of potential indicators for erosion-free status including gender, age of RA onset, RA duration and treatment, use of tobacco, body mass index, functional status, anti-cyclic citrullinated peptide antibody (anti-CPP; an indicator for joint damage), and the 28-joint disease activity score (DAS-28).
As reported in the journal Rheumatology, 21% of the patients were free from erosion at baseline and follow-up.
Analysis showed that erosion-free patients had a significantly shorter duration of RA (3.9 vs 4.6 years), and earlier age at onset (45.0 vs 51.3 years).
Erosion-free patients were also less likely to be positive for anti-CCP than those with joint erosion (46% vs 56%) but this was not statistically significant. There was no significant difference in treatments received by patients with and without joint erosion.
These results were confirmed by multivariate analysis, with the only significant predictive factors for remaining erosion-free being young age at onset and duration of RA.
Each 5-year increase in age at RA onset was associated with a 20% decrease in the likelihood for sustaining erosion-free status, while each 1-year increase in disease duration led to a 14% drop in the likelihood of remaining erosion-free.
Noting that anti-CPP and other factors associated with the likelihood of developing erosion did not significantly predict the likelihood of remaining erosion-free, the authors comment: "Our findings demonstrate that simply taking the converse from studies of worsening erosive disease is not the optimal approach to understanding erosion-free status in RA."
They conclude: "Findings from this study can inform future studies to better characterize this group in other cohorts and provide context for studies on the utility of novel serum and genetic markers in understanding erosion free and erosive disease in RA."
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By Lynda Williams