In this major review of 40 studies, the medication metformin was alone among oral antidiabetic agents to show a significant effect on cardiovascular (CV) risk in a meta-analysis of 40 select controlled trials. This was published in the October 27, 2008 issue of the Archives of Internal Medicine. Metformin reduced CV mortality by 26% relative to any other antidiabetic agent or placebo, but there was no effect on all-cause mortality.
Rosiglitazone (Avandia), another more expensive anti-diabetic medication, actually showed a possible worsened risk of heart disease.
Holistic doctors have used this excellent, old and cheap medication for years for diabetes and insulin resistance (it can also help you lose weight when insulin resistance is present). As it is cheap (available in generic), I suspect this major study will not be seen by many physicians, and that it will be attacked by the drug companies. The main caution with metformin is that it will cause vitamin B12 deficiency, so be sure to take vitamin B12 with it (the amount in a good multivitamin powder should be plenty).
For more information, see the article at Medscape online (free registration required).
Selvin E, Bolen S, Hsin-Chieh Yeh HC, et al. Cardiovascular outcomes in trials of oral diabetes medications: A systematic review. Arch Intern Med. 2008;168:2070-2080.