The findings suggest that metformin is more likely to prevent heart attacks, strokes, and death than glyburide and glipizide. But, because the researchers did not study people who were not taking any diabetes drugs, this study could not determine whether heart attacks, strokes, and death are more or less probable compared with no drug. Factors other than the drugs could have contributed to the differences in heart attacks, strokes, and deaths. However, the researchers did many analyses to find other factors but did not find any. Finally, most study participants were men, so the findings may not apply to women.