Abstract: Objective To investigate the association between Hb/RDW and RPR to disease activity in rheumatoid arthritis（RA） patients.Methods A total of 102 RA patients(RA group) and 103 healthy subjects（control group） were enrolled.The hemoglobin to red cell distribution width ratio(Hb/RDW) and red blood cell distribution width-to-platelet ratio (RPR) were calculated and compared between two groups.Correlation of Hb/RDW and RPR with disease activity and difference of Hb/RDW and RPR before and after treatment in RA patients were analyzed.According to the Hb/RDW and RPR in RA patients,The receiver operating characteristic（ROC） curve were drawn to evaluate the diagnostic function of Hb/RDW and RPR in RA.Results The levels of Hb/RDW in RA group was decreased than those in control group while the RPR was increased（P＜0.05）.With the increase of DAS28, the Hb/RDW and RPR of RA patients decreased（P＜0.05）.Hb/RDW was negative correlated with ESR,CRP and DAS28 in RA patients(r=-0.381,r=-0.214,r=-0.319,all P＜0.05),whereas RPR was negative correlated with ESR,CRP and DAS28 (r=-0.295,r=-0.282,r=-0.278，all P＜0.05).Furthermore,compare with DAS28 before treatment in RA patients,DAS28 score obviously decreased after treatment,whereas Hb/RDW and RPR obviously increased（P＜0.05）.In addition,the area under the ROC curve of Hb/RDW and RPR for diagnosis of RA was 0.863（P＜0.001）and 0.567（P=0.098）.Conclusion The Hb/RDW has good sensitivity and specificity for the diagnosis of RA.Hb/RDW and RPR may be helpful to assess the disease activity and to evaluate the treatment of RA patients.

Key words: Rheumatoid arthritis, Hemoglobin-to-red cell distribution width ratio, Red blood cell distribution width-to-platelet ratio, Disease activity