Association of high-density lipoprotein cholesterol subfractions with insulin resistance in Nigerians with type 2 diabetes mellitus

Background: There are conflicting reports on the relationship of each of the two subfractions of high-density lipoprotein cholesterol (HDL-C) with insulin resistance in patients with type 2 diabetes mellitus (T2DM). Information on the relationship between HDL-C subfractions and insulin resistance in Nigerian patients with T2DM is not available in the literature. Aim: The aim of this article is to determine the association between subfractions of HDL-C and insulin resistance in Nigerian patients with T2DM. Materials and Methods: Patients with T2DM who were being managed by the Endocrinology, Diabetes, and Metabolism unit of the Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi, South-East Nigeria were recruited for this study, whereas individuals with normal glucose tolerance (NGT) were recruited from Nnewi town. The study was carried out within a 5-month period. History was taken and physical examination was done on study participants. Fasting venous samples were collected for plasma glucose, plasma total HDL-C, plasma HDL-C phenotypes, serum C-peptide, serum creatinine, and serum alanine transferase estimation. Homeostasis Model Assessment for Insulin Resistance (HOMA2-IRC-peptide) score was determined using plasma glucose and serum C-peptide concentrations. Data were analyzed using appropriate statistical software. Results: A total of 616 participants consisting of 400 participants with T2DM and 216 participants with NGT were recruited for the study. Difference in age, sex, and blood pressure was not statistically significant between participants with T2DM and those with NGT. There were statistically significant differences in body mass index, fasting plasma glucose, C-peptide, HOMA-IR, total HDL-C, and HDL-C subfractions between subjects with T2DM and those with NGT. There was a significant negative correlation between HOMA-IR score and each of HDL2-C (rs= -0.513, P < 0.01), HDL3-C (rs= -0.471, P < 0.01), and HDL2-C/HDL3-C ratio (rs= -0.416, P < 0.01) in subjects with T2DM. Total HDL-C (odds ratio (OR)=3, P = 0.02), HDL2-C (OR=3.87, P = 0.01), and HDL3-C (OR=2.54, P = 0.02) were significant predictors of insulin resistance in individuals with T2DM after univariate and multivariate logistic regressions. Conclusion: This study showed a negative correlation between insulin resistance and each of the HDL-C subfractions in Nigerian patients with T2DM with HDL2-C having the strongest correlation with HOMA-IR score.