Peripheral Neuropathy Is Associated With High Serum Levels of Small Dense Low-density Lipoprotein-cholesterol in Patients With Type 2 Diabetes Mellitus

Background: A high plasma level of small dense low-density lipoprotein cholesterol (sdLDL-C) is one of the key features of diabetic dyslipidemia. However, the relationship between sdLDL-C and diabetic peripheral neuropathy (DPN) has not been investigated. Therefore, we measured sdLDL-C in patients with type 2 diabetes mellitus (T2DM) ± DPN, determined the factors affecting sdLDL-C levels, and characterized the relationship between sdLDL-C and DPN in T2DM. Methods: : sdLDL-C was measured in the T2DM patients with (n=702) and without (n=780) DPN and the characteristics of these two groups were compared. Correlation analysis was used to identify factors associated with sdLDL-C levels. Finally, multiple regression analysis was used to further characterize the relationship between sdLDL-C and DPN in patients with T2DM. Results: : The serum sdLDL-C levels were higher in T2DM patients with DPN than in those without. sdLDL-C positively correlated with systolic blood pressure, diastolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, urinary microalbumin–creatinine ratio, and urinary microalbumin in T2DM patients with DPN ( P =0.017, P <0.001, P <0.001, P <0.001, P =0.005, and P =0.002, respectively) and negatively correlated with high-density lipoprotein cholesterol ( P =0.01). Furthermore, sdLDL-C was independently associated with DPN in patients with T2DM (odds ratio=5.857, 95% confidence interval [CI]: 2.60–13.20, P <0.001). Receiver operating characteristic analysis was performed to identify the optimal cut-off value of sdLDL-C for the prediction of DPN, which was found to be 0.985 mmol/L (area under the curve=0.571; 95% CI: 0.541–0.600; sensitivity, 64.8%; specificity, 47.7%, P <0.001). Conclusions: : sdLDL-C was increased in T2DM patients with DPN and was found to be an independent predictor of the presence of DPN.