Impact of glucose and lipid markers on the correlation of calculated and enzymatic measured low‐density lipoprotein cholesterol in diabetic patients with coronary artery disease

BACKGROUND AND AIMS: Low-density lipoprotein cholesterol (LDL-C) is widely estimated by Friedewald equation (FE) and Enzymatic test (ET), which are affected by several factors. The aim of this study was to observe the impact of diabetic lipid and glucose patterns on the correlation between FE LDL-C (F-LDL) and ET LDL-C (E-LDL) in patients with coronary artery disease (CAD). METHODS AND RESULTS: A total of 8155 CAD patients were consecutively enrolled and their lipid profiles were measured. The impacts of triglyceride (TG), glycosylated hemoglobin A1c (HbA1c), and high-density lipoprotein cholesterol (HDL-C) on the correlation of F-LDL and E-LDL were examined. The difference value (DV) between F-LDL and E-LDL was compared using ANOVA test. The CAD patients with DM were elder and had higher body mass index, plasma TG compared with those without DM (P < .05 separately). In the whole population, F-LDL was lower than E-LDL but showed a high correlation with E-LDL (r = .970, P = .000). Moreover, as the TG concentrations increased, the DV increased accordingly but the correlation between F-LDL and E-LDL decreased (P < .01). The similar trend was also found in both DM and non-DM patients comparing with different TG groups. However, in patients with DM, there was no significant difference of DV in different HbA1c groups or HDL-C concentrations (P > .05). CONCLUSION: Although F-LDL might underestimate the value of LDL-C, the correlation between F-LDL and E-LDL was clinically acceptable (r = .97), suggesting the LDL-C values measured by two methods were similarly reliable in CAD patients with or without DM.