CP and rheumatoid arthritis: In addition, ROC curve analysis revealed that the combined detection of RA-CP, HRR, and anti CCP antibody achieved the highest area under the ROC curve (AUC<sub>RA - CP + HRR + antiCCP antibody</sub> = 0.998) for the diagnosis of RA and also improved the diagnostic sensitivity (98.31%).<h4>Conclusion</h4>RA-CP and HRR were identified as independent predictors of RA, including RA-CP as a risk factor for RA and HRR as a protective factor for RA.