Red blood cell distribution width: a potential laboratory parameter for monitoring inflammation in rheumatoid arthritis

Correlation analysis of red blood cell distribution width (RDW) and C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), tumor necrosis factor α (TNF-α), interleukin (IL)-6, and IL-10 in rheumatoid arthritis (RA) to investigate whether RDW can serve as a potential parameter for indicating inflammation in RA patients. A total of 670 RA patients from October 2014 to April 2016 were enrolled in our study. The white blood cell (WBC), red blood cell (RBC), platelet (PLT), hemoglobin (HGB), RDW, CRP, and ESR in peripheral blood of patients with RA were retrospectively analyzed. The relative expression of TNF-α, IL-6, and IL-10 was detected by RT-qPCR. Correlation analysis between RDW and CRP, ESR, TNF-α, IL-6, and IL-10 in RA was conducted by Microsoft Excel. RDW level was significantly increased in RA patients compared to osteoarthritis (OA) patients (P < 0.001) and healthy donors (HDs) (P < 0.001), and RDW was positively associated with inflammatory markers, such as CRP and ESR. In ROC curve analysis, the area under the curve (AUC) of RDW for the identification of RA was 0.881, with a 95% confidence interval (CI) from 0.864 to 0.898. Moreover, correlation analysis showed that RDW level was positively associated with TNF-α and IL-6, however negatively associated with IL-10. RDW was increased in patients with RA which was associated with inflammation in RA, suggesting that RDW may be a potential auxiliary marker for indicating inflammation process in RA conveniently.