A major new study from scientists at Northwestern University has raised fresh concerns about the safety of two widely used medicines for type 2 diabetes.
The research suggests that older, commonly prescribed drugs—called sulfonylureas and basal insulin—may increase the risk of serious heart problems, including heart attacks, strokes, heart failure, and even amputations.
Type 2 diabetes is a long-term condition that affects how the body uses insulin. Insulin is a hormone that helps move sugar from the blood into the body’s cells, where it is used for energy.
When the body cannot use insulin properly, blood sugar levels rise. Over time, high blood sugar can damage blood vessels and organs, including the heart, kidneys, eyes, and nerves. This is why managing blood sugar is so important for people living with diabetes.
For most patients, doctors begin treatment with a medicine called metformin. Metformin has been used for many years and is generally considered safe, effective, and affordable. It helps lower blood sugar and may even provide some protection for the heart.
However, not everyone can take metformin. Some people experience side effects, while others need an additional medication because metformin alone is not enough to control their blood sugar.
When patients need a second drug, doctors often prescribe sulfonylureas or basal insulin. These medications have been available for decades and are much less expensive than newer diabetes drugs. For this reason, they are still very commonly used around the world.
In the new study, researchers examined real-world health data from more than 130,000 adults with type 2 diabetes who needed a second medication after metformin.
The team compared six different types of second-line diabetes drugs to see how they affected heart health. This is the first large study to directly compare these medications in such a broad group of patients outside of a traditional clinical trial setting.
The results were concerning. Patients who took sulfonylureas were 36 percent more likely to experience serious heart-related events compared to those who were given newer drugs known as DPP-4 inhibitors. Even more alarming, people who used basal insulin had about double the risk of these serious heart problems.
The heart-related events included heart attacks, strokes, heart failure, and amputations caused by poor blood circulation. These are life-changing and sometimes life-threatening complications.
Because around 60 percent of patients who need a second diabetes medication are prescribed sulfonylureas or basal insulin, the potential impact of these findings is very large.
One reason these older drugs remain popular is cost. Sulfonylureas and basal insulin are far cheaper than many newer diabetes medicines.
For patients without strong insurance coverage, and for health systems trying to control spending, these lower prices can be appealing. However, the study suggests that lower upfront costs may come with higher long-term health risks.
The researchers point to several newer medications that appear to be safer for the heart. These include GLP-1 receptor agonists such as liraglutide, SGLT-2 inhibitors such as empagliflozin, and DPP-4 inhibitors such as sitagliptin. Previous research has shown that some of these newer drugs can reduce the risk of heart disease in people with diabetes.
The study was published in JAMA Network Open. Because it used real-world patient data rather than only clinical trial data, the findings reflect what happens in everyday medical practice. This makes the results especially meaningful for doctors and patients making treatment decisions.
Dr. Matthew O’Brien, who led the study, said the findings should encourage careful discussion between doctors and patients when choosing a second diabetes medication. Lowering blood sugar remains very important, but treatment choices should also consider long-term heart health.
People living with type 2 diabetes are encouraged to talk with their healthcare providers about the benefits and risks of their medications. With many treatment options now available, choosing the safest and most effective therapy can help protect not only blood sugar levels but also the heart and overall health.
If you care about diabetes, please read studies about bananas and diabetes, and honey could help control blood sugar.
For more health information, please see recent studies about Vitamin D that may reduce dangerous complications in diabetes and results showing plant-based protein foods may help reverse type 2 diabetes.
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