Metformin has been found the most effective type 2 diabetes drug.
A recent meta-analysis comparing type 2 diabetes drugs metformin and sulfonylurea found that metformin significantly reduced the relative risk of patient death from heart disease.
Heart attacks, strokes, and other cardiovascular fatalities are major risks for patients with type 2 diabetes. Prior to this study, it was unclear if any diabetes drugs were superior at preventing this type of death.
The analysis evaluated 204 other studies that were mostly short term, with only 22 lasting more than 2 years. Generally, patients in these studies were overweight and had uncontrolled blood sugar levels.
Since meta-analyses can be limited, researchers only included studies using similar methods and excluded studies that included patients taking any diabetes drugs unrelated to the study.
Researchers analyzed cardiovascular disease and drug effects, such as glucose control, and common side effects, such as weight gain, hypoglycemia, and gastrointestinal problems.
Researchers also evaluated how the drugs worked, either individually or with another drug.
DPP-4 inhibitors were much less effective at lowering blood sugar levels compared with metformin and sulfonylureas, according to the study.
SGLT-2 inhibitors caused yeast infections in 10% of users. SGLT-2 inhibitors and GLP-1 receptor antagonists were found to help patients lose weight.
Sulfonylureas was shown to cause weight gain and had the highest rates of hypoglycemia among oral medications studied.
Metformin was found to work as well, if not better, than sulfonylureas and more recent diabetes drugs.
These findings support the recommendation that metformin be used as a first-line therapy, according to the study.
"Metformin looks like a clear winner," said Nisa Maruthur, MD, MHS, assistant professor of medicine at the Johns Hopkins University School of Medicine. "This is likely the biggest bit of evidence to guide treatment of type 2 diabetes for the next 2 to 3 years."
Though these findings are significant, researchers concluded that the question is now which medication is to be used in combination with metformin.