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Use of glipizide and metformin can increase the incidence of cardiovascular events. In a study of non-diabetic African Americans with insulin resistance, the long-term use of oral antidiabetic agents was associated with an increase in aortic pulse wave velocity (PWV), which is consistent with a decrease in the elastic properties of the aorta.
"It has been shown previously that increased PWV is an indicator of a high incidence of cardiovascular events and an independent predictor of cardiac mortality." Therefore, "the use of oral antidiabetic agents for the prevention of cardiovascular complications in non-diabetic African Americans with insulin resistance needs to be critically evaluated," they conclude.
It has been suggested that improving insulin sensitivity, perhaps with oral antidiabetic agents, in insulin resistant non-diabetic individuals may delay the development of diabetes and its related cardiovascular complications. But data are lacking on the long-term cardiovascular effects of these agents in non-diabetic populations.
To investigate, Dr. Harisios Boudoulas from the Academy of Athens in Greece and associates randomly assigned 181 normoglycemic African Americans, but with insulin resistance, to glipizide (5 mg/day), metformin (500 mg/day) or placebo for 24 months.
They observed a significant increase in aortic PWV in both glipizide- and metformin-treated subjects, with p values of 0.012 and 0.01, respectively. In contrast, aortic PWV remained unchanged in the placebo arm. The increase in PWV in the two active treatment arms was significant relative to placebo (analysis of variance p < 0.05).
"No other cardiovascular or metabolic variable changed significantly during the follow up period," they note.
In a multivariate analysis, treatment with glipizide or metformin "was the only independent predictor of changes in PWV during the follow up period."
The investigators note that the precise mechanism or mechanisms responsible for the effects of these agents on aortic function are unknown and deserve further study.
Heart 2005;91:589-594.