Oxidized Low-Density Lipoprotein (ox-LDL) to LDL Ratio (ox-LDL/LDL) and ox-LDL to High-Density Lipoprotein Ratio (ox-LDL/HDL).

BACKGROUND: Oxidized low-density lipoprotein (ox-LDL) plays a principal role in diabetes complications, though ox-LDL concentrations and its functions are dependents of other oxidative and anti-oxidative particles. The oxLDL to low-density lipoprotein ratio (ox-LDL/LDL) and ox-LDL to high-density lipoprotein ratio (ox-LDL/HDL) as new lipid biomarkers may serve as a good estimation of oxidation and anti-oxidation in type 2 diabetes mellitus. The aim of this study was first to examine ox-LDL/LDL and ox-LDL/HDL levels in patients with type 2 diabetes mellitus compared to a control group and evaluate their diagnostic accuracies, and, second, to investigate the correlation of these two ratios with triglyceride and HDL levels.

METHODS: This study was included 144 patients admitted to the diabetes clinic of a University general hospital and 41 healthy individuals as controls. Levels of LDL, HDL, triglyceride (TG) ox-LDL, and malondialdehyde (MDA) were measured for all patients. Levels of ox-LDL/LDL and ox-LDL/HDL were calculated. Diagnostic accuracies were determined by receiver-operating characteristic curve analysis by measuring the area under the curve.

RESULTS: Ox-LDL, ox-LDL/LDL, and ox-LDL/HDL were significantly higher in patients compared to the control group after adjustment for age, gender, and BMI (p = 0.000). The area under the curve for diagnosing diabetes was 0.946 for ox-LDL/HDL, 0.918 for ox-LDL/LDL, and 0.832 for ox-LDL. Ox-LDL/HDL was positively correlated with MDA (r = 0.210, p = 0.011). Ox-LDL/LDL was negatively correlated with HDL (r = -0.2 p = 0.016) and positively correlated with TG (r = 0.45 p = 0.000). Ox-LDL/HDL and TG had significant positive correlation (r = 0.173 p = 0.037). The ox-LDL/LDL level was significantly higher in patients with coronary heart disease (CHD) or hypertension (HTN) compared to those without (p = 0.042).

CONCLUSIONS: Our findings revealed that ox-LDL/LDL and ox-LDL/HDL are potent biomarkers of type 2 diabetes, which apparently reflect the association between lipids in the state of oxidative stress.