"Additional data needs to be brought to bear," researcher Theodore Mazzone, MD, says in a news release.
"However," he adds, "this is very helpful for suggesting that [Actos] could be a useful, novel approach for managing cardiovascular risk in patients with diabetes."
Mazzone works at the University of Illinois at Chicago Medical School.
The study appears in The Journal of the American Medical Association.
Different Methods of Action
The study's two drugs work differently.
Actos was approved by the FDA in 1999. Glimepiride was approved in 1995.
Mazzone's team studied a racially diverse group of Chicago-area diabetes patients.
When the study started, the patients were 60 years old, on average. They had "good" blood sugar control and most were using diabetes drugs, the researchers note.
The researchers gave the patients Actos or glimepiride for 18 months.
The carotid artery wall's thickness is a measure of atherosclerosis (hardening of the arteries), the researchers note.
"The less the thickening, and the slower the rate of thickening, the less risk of heart attack in general," Mazzone says in a university news release.
Few side effects -- and no heart-related deaths -- were reported in either group. However, both drugs can have side effects.
Patients taking Actos gained slightly more weight (7 pounds) than those taking glimepiride (about 2 pounds), on average.
The study was funded by Takeda Pharmaceuticals North America, which makes Actos. Takeda is a WebMD sponsor.