More than 500 million people around the world live with diabetes, and most people with type 2 diabetes depend on medication to keep their blood sugar under control.
For many years, doctors have focused mainly on lowering blood sugar levels to prevent complications. However, new research suggests that some commonly used diabetes medications may come with an unexpected risk: they could increase the chances of developing serious heart problems.
Scientists at Northwestern University have found that two widely prescribed diabetes treatments, known as sulfonylureas and basal insulin, may significantly increase the risk of heart attacks, strokes, and heart failure when compared with some newer diabetes medications.
Type 2 diabetes is one of the most common chronic diseases worldwide. It develops when the body becomes resistant to insulin or cannot use insulin effectively. Insulin is a hormone that helps move sugar from the bloodstream into cells, where it is used for energy. When insulin does not work properly, blood sugar levels rise and can remain high for many years.
Over time, high blood sugar can damage blood vessels throughout the body. This damage increases the risk of heart disease, stroke, kidney disease, vision problems, and nerve damage. In fact, heart disease remains the leading cause of death among people with type 2 diabetes.
For most patients, treatment begins with a medication called metformin. Metformin has been used for decades and is considered the first-choice treatment for type 2 diabetes. It helps lower blood sugar and improves the body’s response to insulin.
However, diabetes often progresses over time, and many people eventually need a second medication to maintain healthy blood sugar levels.
Two of the most commonly prescribed second-line treatments are sulfonylureas and basal insulin. Sulfonylureas work by stimulating the pancreas to release more insulin. Basal insulin, often called long-acting insulin, provides a steady supply of insulin throughout the day and night to help keep blood sugar stable.
Because these medications have been available for many years, they are generally less expensive than newer treatments and are widely prescribed around the world. However, researchers wanted to know whether different second-line diabetes drugs have different effects on heart health.
To answer this question, the Northwestern team analyzed medical data from more than 132,000 adults with type 2 diabetes. All participants had already been taking metformin and needed an additional medication to improve blood sugar control.
The study is particularly important because it examined what happens to patients in real-world healthcare settings rather than only in highly controlled clinical trials. This allowed researchers to better understand how these medications affect everyday patients.
The results revealed important differences between the drugs.
People who used sulfonylureas had a 36 percent higher risk of experiencing a major cardiovascular event compared with those who used DPP-4 inhibitors, a newer class of diabetes medications. Major cardiovascular events included heart attacks, strokes, and heart failure.
The findings were even more concerning for people taking basal insulin. These patients were about twice as likely to experience a serious cardiovascular event compared with people taking DPP-4 inhibitors.
To better understand the practical impact of these findings, the researchers calculated how often these events occurred. Among patients taking basal insulin, one major cardiovascular event occurred for every 37 people treated over a two-year period. For patients taking sulfonylureas, one event occurred for every 103 people during the same period.
Although these numbers may seem small at first glance, they become much more significant when applied to large populations. In the United States alone, more than 30 million people live with type 2 diabetes. Even a modest increase in cardiovascular risk could affect a very large number of individuals.
The study’s lead author, Dr. Matthew O’Brien, believes the findings should encourage doctors and patients to look beyond blood sugar control when choosing diabetes treatments. According to the researchers, the ideal diabetes medication should not only lower blood sugar but also help protect the heart.
Over the past decade, several newer classes of diabetes medications have become available. These include GLP-1 receptor agonists, SGLT-2 inhibitors, and DPP-4 inhibitors.
Many studies have shown that some of these newer medications can lower cardiovascular risk and, in certain cases, even reduce the chances of heart attacks, heart failure, and death from cardiovascular disease.
Despite these benefits, newer diabetes drugs are often much more expensive than older medications. Cost remains one of the biggest barriers preventing wider use of these treatments. As a result, many patients continue to receive older medications because they are more affordable and more familiar to healthcare providers.
However, the researchers argue that the higher upfront cost of newer medications may be balanced by long-term savings from preventing expensive medical problems such as heart attacks, strokes, hospitalizations, and heart failure treatment.
The study highlights an important shift in how doctors think about diabetes treatment. In the past, lowering blood sugar was the main goal. Today, many experts believe treatment decisions should also consider heart health, kidney health, quality of life, and long-term safety.
The researchers emphasize that patients should not stop taking their medications without speaking to their doctor. Every patient’s situation is different, and treatment decisions should be based on individual health needs, medical history, and financial considerations.
For people living with type 2 diabetes, the findings serve as a reminder that managing the disease involves more than monitoring blood sugar alone. Understanding the benefits and risks of different treatment options may help patients make informed decisions together with their healthcare providers.
The study was published in the journal JAMA Network Open. Its findings suggest that when metformin is no longer enough, choosing the right second medication could play an important role not only in controlling diabetes but also in protecting the heart and improving long-term health outcomes.
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