Red Blood Cell Distribution Width-to-Platelet Ratio Inversely Correlates with Indicators of Disease Activity Status in Rheumatoid Arthritis Patients

Introduction: Present study was performed to verify red blood cell distribution width-toplatelet ratio (RPR) level in rheumatoid arthritis (RA) patients and to examine its correlation with clinical and biochemical indicators of disease activity status. Methods: In this cross-sectional analytical study, 67 patients with RA and 34 age- and gender-matched healthy control subjects were enrolled. Based on the disease activity score 28-ESR (DAS28-ESR), RA patients were divided into subgroups: low disease activity (n=20), moderate disease activity (n=22) and high disease activity (n=25). Laboratory tests included erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) concentration, platelet count (PLT), red blood cells count (RBC), red blood cells distribution width (RDW) and fibrinogen concentration. Statistical analyses were carried out using SPSS 13 software. Statistical significance was set at a p-value less than 0.05. Results: There was statistically significant difference (p=0.006) between RPR in RA patients with different stages of disease activity, with higher values in patients with low disease activity. The RPR showed statistically significant negative correlations with ESR (rho= -0.309; p=0.012), CRP (rho= -0.421; p=0.001), swollen joint count - SJC (rho = -0.368; p=0.002) and tender joint count - TIC (rho= -0.355; p=0.003), DAS28-ESR (rho= -0.409; p=0.001), DAS28-CRP (rho= -0.422; p<0.0005) and Visual analogue scale - VAS (rho= 0.260; p=0.033) in RA patients. Conclusion: The present study provided evidence that the lower RPR values in RA patients are significantly associated with the disease activity indicators.