The effects of oral anti-hyperglycaemic medications on serum lipid profiles in patients with type 2 diabetes

Aim: Patients with type 2 diabetes often have dyslipidaemia, putting them at risk of cardiovascular disease, and are frequently treated with oral anti-hyperglycaemic medications (OAMs). This review compares the effects of OAMs on serum lipids [total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TGs) and free fatty acids (FFAs)] in patients with type 2 diabetes. Methods: MEDLINE was searched for entries indexed from January 1966 to November 2002; search terms included the names of OAMs and serum lipids, limited to English language and human subjects. We selected clinical studies in type 2 diabetes of OAM monotherapy that included serum lipid data, treated all patients in a treatment group with the same drug, used therapeutic OAM doses not higher than the maximum recommended in the USA, compared therapy with baseline or placebo and specified statistical tests used. One unblinded investigator selected studies for inclusion. Data reported include number of patients, study length, OAM dose, serum lipid data at baseline and endpoint, p-values and statistical tests. Results: Data on the serum lipid effects of sulphonylureas, repaglinide, nateglinide and miglitol were inconclusive. Acarbose increased HDL-C and decreased LDL-C and voglibose reduced TC. Metformin at higher doses reduced TC; data on its effects on other lipids were inconclusive. Rosiglitazone increased LDL-C, HDL-C and TC and reduced FFAs but had no effect on TGs. Pioglitazone increased HDL-C and reduced TGs and FFAs but did not affect LDL-C or TC. Conclusions: Lipid changes as a result of improved glycaemic control are not uniform findings associated with anti-diabetic therapy. Only metformin, acarbose, voglibose, rosiglitazone and pioglitazone had significant effects on the lipid profile. These effects should be considered when selecting OAMs for patients with type 2 diabetes.