Oxidative Stress‐Related HDL Dysfunction in Hemodialysis: The Clinical Utility of MPO / PON1 and MPO / HDL ‐C Ratios in Cardiovascular Risk Assessment

ABSTRACT Introduction Oxidative stress (OS), inflammation, and lipoprotein dysfunction contribute to the high cardiovascular disease (CVD) risk in chronic kidney disease (CKD) patients undergoing hemodialysis (HD). This study examined whether OS‐related biomarkers—myeloperoxidase (MPO), paraoxonase‐1 (PON1), and homocysteine (HCY)—and their derived ratios (MPO/PON1, MPO/HDL‐C, PON1/HDL‐C) are associated with cardiovascular risk. Methods A case–control study was conducted including 42 HD patients and 42 matched healthy controls. Plasma HCY levels, MPO activity, and PON1 activity were measured, along with lipid profiles. Functional OS ratios were calculated. Results HD patients showed higher MPO activity and HCY levels and lower PON1 activity compared with controls ( p < 0.001). MPO/PON1 and MPO/HDL‐C ratios were significantly elevated before and after dialysis, indicating increased oxidative imbalance. Conclusion The MPO/PON1 ratio may represent a novel biomarker of OS and CVD risk in HD patients, supporting the evaluation of HDL functionality for improved risk stratification.