A leptin-adjusted multibiomarker disease activity (MBDA) score significantly improved prediction of radiographic disease progression for patients with rheumatoid arthritis (RA), according to results published in Rheumatology.
The researchers developed 2 models to adjust MBDA score for age, sex, and adiposity: one model used serum leptin concentration as a proxy for adiposity, and the other used body mass index (BMI).
The study included 2 cohorts. The first cohort consisted of participants with RA who had undergone commercial MBDA testing and had data for age, sex, and serum leptin concentration (n=325,781), and this cohort was used for both models. An additional cohort of participants from 5 studies or registries with BMI data was used only for the BMI-adjusted MBDA score (n=1411).
The researchers used univariate and multivariate linear regression analyses to assess the adjusted MBDA scores and conventional clinical measures as predictors of radiographic progression, which was assessed in terms of modified total Sharp score (mTSS).
In pairwise regression analyses, the researchers found that the leptin-adjusted (P =.00066) and BMI-adjusted (P =.0027) MBDA scores were significant independent predictors of mTSS, after adjusting for the 28-joint Disease Activity Score using C-reactive protein (DAS28-CRP). However, DAS28-CRP was not a significant independent predictor of mTSS after adjusting for leptin-adjusted (P =.74) or BMI-adjusted (P =.87) MBDA score.
The results also indicated that the leptin-adjusted MBDA score significantly predicted mTSS after adjusting for the BMI-adjusted MBDA score (P =.025) or the original MBDA score (P =.027), but the opposite was not true.
“These results suggest that the leptin-adjusted MBDA score represents an improvement over both the original MBDA score and commonly used disease activity measures for predicting radiographic progression in RA,” the researchers wrote.
Curtis JR, Flake II DD, Weinblatt ME, et al. Adjustment of the multi-biomarker disease activity score to account for age, sex and adiposity in patients with rheumatoid arthritis [published online December 24, 2018]. Rheumatology. doi: 10.1093/rheumatology/key367