A large study from Northwestern University has raised new questions about the safety of two older treatments widely used for type 2 diabetes.
The researchers found that people who added sulfonylureas or basal insulin after taking metformin had a higher risk of serious heart and blood vessel problems than people who used some newer diabetes medicines.
Type 2 diabetes develops when the body does not respond well to insulin or cannot make enough of it. Insulin helps move sugar from the bloodstream into cells, where it can be used for energy. When blood sugar stays too high for years, it can damage blood vessels, nerves and major organs.
This damage helps explain why people with diabetes have a higher risk of heart attack, stroke, heart failure, kidney disease and circulation problems. Good diabetes care therefore involves more than simply lowering blood sugar. Doctors also try to reduce the patient’s long-term risk of damage to the heart and other organs.
Metformin is often the first medicine prescribed for type 2 diabetes because it is effective, inexpensive and has been used for decades. But some people cannot tolerate it, and many eventually need another medicine because metformin alone no longer keeps their blood sugar under control.
For many years, common second choices have included sulfonylureas and basal insulin. Sulfonylureas encourage the pancreas to release more insulin, while basal insulin provides a steady background supply of insulin throughout the day. Both treatments are relatively familiar and affordable, which helps explain their widespread use.
In the study, researchers examined health information from more than 130,000 adults with type 2 diabetes who needed a second medicine after metformin. They compared six groups of diabetes treatments and looked for major problems involving the heart and blood vessels.
The researchers found that people taking sulfonylureas had a 36% higher risk of serious heart and circulation problems compared with people taking DPP-4 inhibitors, another type of diabetes medicine. People using basal insulin had about twice the risk.
The problems studied included heart attacks, strokes, heart failure and amputations linked to poor blood flow. These complications can cause lasting disability and can sometimes be life-threatening.
The findings matter because sulfonylureas and basal insulin are still commonly prescribed. Their lower price can make them attractive to patients and health systems, especially when newer medicines are expensive or difficult to access.
However, diabetes treatment has changed greatly in recent years. Newer drug groups include GLP-1 medicines, SGLT-2 inhibitors and DPP-4 inhibitors. Some medicines in these groups have shown benefits beyond blood sugar control, including protection for the heart or kidneys in certain patients.
The research was published in JAMA Network Open. Because the study examined health records from routine medical care rather than relying only on people enrolled in a controlled clinical trial, it offers a useful picture of how these medicines may perform in everyday practice.
Still, this type of study cannot prove that the older drugs directly caused the additional heart problems. Patients who receive insulin or sulfonylureas may differ from those receiving newer drugs in ways that also affect their health risks. The findings therefore add evidence to the discussion rather than providing a reason for patients to stop treatment on their own.
Study leader Dr. Matthew O’Brien said treatment decisions should consider more than the ability of a medicine to lower blood sugar. Cost, side effects, other health conditions and possible long-term effects on the heart can all matter when choosing a second diabetes drug.
For people with type 2 diabetes, the main message is to discuss treatment choices with a healthcare professional. A medicine that works well for one person may not be the best choice for another, and changing or stopping diabetes medication without medical advice can be dangerous.
If you care about diabetes, please read studies about 5 vitamins that may prevent complication in diabetes, and how to manage high blood pressure and diabetes with healthy foods.
For more health information, please see recent studies about vitamin D and type2 diabetes, and to people with type 2 diabetes, some fruits are better than others.
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