Models to predict SSc progression developed
medwireNews: Researchers have produced two models for the prediction of progressive skin thickening in patients with systemic sclerosis (SSc) using data from the European Scleroderma Observational Study.
Ariane Herrick (University of Manchester, UK) and study co-authors found that the 66 patients who experienced disease progression – defined as a 5-point and 25% increase in modified Rodnan skin score (mRSS) over 12 months – had a significantly shorter median disease duration (8.1 vs 12.6 months) and lower mRSS scores (19 vs 21 points) than the 227 patients who did not.
In a logistic regression analysis, a model combining mRSS score, SSc duration, and an interaction between the two factors correctly distinguished between patients who progressed and those who did not on 66.6% of occasions, with a sensitivity of 73.4% and specificity of 57.2%.
When positivity for anti-RNA polymerase III antibodies (Pol3+), which was associated with a significantly higher mRSS score than positivity for other autoantibodies, was included as a variable, the sensitivity decreased and the specificity increased, to 60.4% and 74.2%, respectively, and this second model correctly identified progressors on 71.1% of occasions.
The first model “will be the more useful for studies aiming for cohort enrichment,” whereas the second “will help to identify patients at higher risk for mRSS progression in a clinical setting,” write the researchers in the Annals of the Rheumatic Diseases.
And they conclude that these findings provide “a valuable message for clinicians that patients with short disease duration and Pol3+ must be especially closely monitored.”
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