Comparison of lipid profiles and lipoprotein [a] levels in patients with type 2 diabetes mellitus during oral hypogrlycemic or insulin therapy

ABSTRACT

The aim of this study is to compare lipid and lipoprotein [a] profiles in patients with type 2 diabetes mellitus [DM] on insulin and oral hypoglycemic therapy. The study took place in the Department of Physiology, Army Medical College, Rawalpindi, Pakistan, during 2002. Ninety-seven type 2 DM patients participated in the study. We divided the patients according to the type of treatment into sulphonylurea [n=40], sulphonylurea plus metformin [n=33] and insulin [n=24] therapy groups as well as 40 healthy subjects served as controls. Fasting blood samples were analyzed for lipoprotein [a] [Lp [a]], total cholesterol [TC], triglycerides [TG], low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], glucose, glycosylated hemoglobin [HbA1c] and insulin. Different groups of diabetic patients showed elevated fasting blood glucose [FPG] levels [p<0.0001 for all], HbA1c [p<0.0001 for all] compared with controls. Meanwhile, fasting insulin levels were elevated only in insulin treated group compared with oral hypoglycemic treated groups and controls [p<0.0001 for all]. Patients on sulphonylurea and on sulphonylurea plus metformin groups showed significantly elevated TC [p<0.001, p<0.0001], TG [p<0.001, p<0.01], LDL-C [p<0.01, p<0.001] and LDL-C/HDL-C [p<0.0001, p<0.0001] compared with controls. Insulin therapy group showed significantly decreased TC, TG, LDL-C, LDL-C/HDL-C levels compared with sulphonylurea and sulphonylurea plus metformin treated groups, however, no significant difference was noted in the levels of above mentioned parameters and controls. Meanwhile, HDL-C levels were significantly lower in all diabetic groups compared with controls and were higher in insulin treated group compared with sulphonylurea plus metformin therapy group [p<0.05]. Lipoprotein [a] levels were significantly higher in different diabetic groups compared with controls. While there was a non-significant difference in Lp [a] levels between different diabetic groups. Patients with type 2 DM who are being treated on insulin have a better lipid profile [TC, HDL-C, LDL-C, TG] compared with those patients on oral hypoglycemic agents. Meanwhile, Lp [a] levels were raised in all diabetic patients and seem not to be affected either by insulin or by oral hypoglycemic treatment