Head-to-Head Study Finds Which Diabetes Meds Are Best for the Heart
There are many medications for type 2 diabetes, but one class may stand out for protecting the heart, a new study suggests.
The study, of thousands of U.S. veterans with diabetes, found that those who added drugs called GLP-1 receptor agonists to their usual regimen were somewhat less likely to suffer a first-time heart attack or stroke in coming years.
That was in comparison to vets who added either of two other types of diabetes drug.
GLP-1 receptor agonists are a newer class of drug for type 2 diabetes and include medications like dulaglutide (Trulicity), liraglutide (Victoza) and semaglutide (Ozempic). They are usually taken by injection.
The drugs are already recommended options for people with type 2 diabetes who either have heart disease or are at high risk of it -- due to additional conditions like high blood pressure or obesity.
Experts said the new findings -- published May 9 in the Annals of Internal Medicine -- do not mean that all diabetes patients with heart risk factors should be on a GLP-1 drug.
For one, the study was not a clinical trial that tested which type of diabetes medication is best for preventing first-time heart trouble.
But the findings do show that GLP-1 drugs are associated with a better cardiovascular outlook than other medications are, according to senior researcher Dr. Christianne Roumie.
"I think these findings are important for the care of patients with diabetes," said Roumie, a professor of medicine at Vanderbilt University Medical Center in Nashville, Tenn.
She said the results may encourage more doctors to consider GLP-1 drugs as an "add-on" treatment to help prevent heart disease.
More than 37 million Americans have diabetes, and the vast majority have the type 2 form, according to government figures.
Type 2 diabetes arises when the body can no longer properly use the hormone insulin, which regulates blood sugar. Over time, chronically high blood sugar can damage the blood vessels and contribute to complications like heart and kidney disease.
For years, the first-line therapy for type 2 diabetes has been metformin -- an inexpensive oral drug that lowers blood sugar.
But in recent years, new options have emerged. Besides GLP-1 drugs, there is a class of medications called SGLT2 inhibitors, which include oral medications like canagliflozin (Invokana), dapagliflozin (Farxiga) and empagliflozin (Jardiance).
The latest guidelines from the American Diabetes Association and other groups now recommend both of those drug classes as options for people at high risk of heart disease.
That was based on trials showing that the drugs can lower the risk of complications like heart attack, stroke and heart failure.
What's not clear, Roumie said, is how the drugs stack up against one another.
Her team tried to find out by looking at medical records from thousands of U.S. veterans treated for diabetes between 2001 and 2019.
All were first on a standard, older medication, like metformin or insulin, then had another drug added: either a GLP-1 or SGLT2 medication, or another relatively newer type of diabetes drug called a DPP-4 inhibitor (drugs like sitagliptin (Januvia) and saxagliptin (Onglyza).
Over eight years, patients on GLP-1 drugs were 18% less likely to suffer first-time heart problems or stroke, versus those on a DPP-4 drug. Those on SGLT2 medications showed no such benefit, however.
Dr. Bryan Blase is an endocrinologist at NYU Langone Brooklyn who regularly sees patients with diabetes. Given prior studies, he said he was not surprised GLP-1 drugs were linked to heart benefits.
In his own experience, Blase said the medications do a particularly good job at lowering patients' A1C levels -- a measure of long-term blood sugar control.
He was surprised, though, that SGLT2 drugs were not associated with a better cardiovascular outlook, versus DPP-4 drugs.
According to researcher Roumie, DPP-4 medications are considered to be "neutral" in terms of heart health. In contrast, it's thought that GLP-1 and SGLT2 drugs might have heart-protecting effects that go beyond blood sugar control -- by reducing inflammation or improving blood vessel function, for example.
Blase said he tends to favor GLP-1 drugs, but the reality is, diabetes medication choices often come down to health insurance. Both of the newer drug classes cost hundreds to around $1,000 per month, he noted.
"Insurance coverage is probably the most important factor," Blase said. "If insurance won't pay, most people cannot afford these drugs."
Where studies like this one might help, he said, is in encouraging insurance plans to cover the newer medications: If they can prevent some cases of heart disease and stroke, that could be a good financial investment.
The study, which was funded by the U.S. Department of Veterans Affairs, does have limitations. A key one is that the patients were mostly white men. Both Roumie and Blase said more research is needed to know whether the findings are similar for women and people of other races.
The U.S. Centers for Disease Control and Prevention has more on managing diabetes.
SOURCES: Christianne Roumie, MD, MPH, professor, medicine, Vanderbilt University Medical Center, Nashville, Tenn.; Bryan Blase, MD, endocrinologist, NYU Langone Brooklyn Medical Arts Pavilion, adjunct instructor, medicine, NYU Grossman School of Medicine, New York City; Annals of Internal Medicine, May 9, 2023