Associations between the use of metformin, sulphonylureas, or diet alone and cardiovascular outcomes in 6005 people with type 2 diabetes in the FIELD study

Aims: We aimed to determine the associations between metformin or sulphonylurea monotherapy at study entry into the FIELD diabetes trial and (1) metabolic risk factors, (2) risk of a first major cardiovascular (CVD) outcome, and (3) the effect of each therapy on the risk-modifying effect of fenofibrate. Methods: Patients receiving metformin or sulphonylureas without insulin therapy were compared for the relative risk of CVD outcomes, adjusted for differences in baseline characteristics likely to affect risk. Results: Metformin-treated patients were likely to be younger, female, or obese. Metformin was associated with higher levels of lipids (other than LDL-C) and homocysteine (P< 0.001). Sulphonylurea-treated patients had a longer history of diabetes and more CVD and microvascular disease. Sulphonylurea treatment was associated with higher plasma creatinine and lower plasma HDL-C (P< 0.001). The risks of all CVD outcomes were higher for those on sulphonylureas than diet alone, but were nonsignificant after adjustment for the duration and intensity of diabetes and severity of risk factors. Metformin and sulphonylureas did not significantly influence the benefits of fenofibrate on CVD outcomes. Conclusions: Apparent differences in the risk of CVD outcomes associated with oral hypoglycemics therapy were largely abolished by adjustment for diabetes and CVD risk factors.