Are Diabetes Medicines Related to Risks for Heart Disease?

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Chiquette E, Ramirez G, Defronzo R.: A meta-analysis comparing the effect of thiazolidinediones on cardiovascular risk factors. Arch Intern Med 164(19):2097-2104, 2004.

What is the problem and what is known about it so far?

People with type 2 diabetes have an increased chance of developing heart and blood vessel problems. Many people with diabetes take a type of medication called "thiazolidinedione" to help control their blood glucose levels. It is not known if these medications also help people ward off heart and blood vessel problems, such as high cholesterol, high blood pressure, and excess weight.

The researchers wanted research previous studies to see how two diabetes medications affect a patient's chance of developing heart and blood vessel problems.

Who was studied?

This study was a review of 23 trials. Each trial included at least 30 adults with type 2 diabetes. These studies included a total of 8,000 people.

How was the study done?

The researchers looked at the effects of two medicines on nine health conditions. One medicine is called "pioglitazone," and the other is called "rosiglitazone." Then the researchers looked to see if using one medicine had a different effect on these symptoms than using the other.

What did the researchers find?

Both medications helped patients decrease their blood glucose levels and caused patients to gain weight.

Pioglitazone did not have much effect on patients' levels of fat and cholesterol in the blood.

Rosiglitazone increased patients' LDL cholesterol (“bad” cholesterol), total cholesterol, and HDL cholesterol (“good” cholesterol) levels. It did not have an effect on patients’ triglyceride levels (a measure of fat in the blood).

No information was available on the effect that pioglitazone had on blood pressure. Rosiglitazone did not have an effect on blood pressure

What were the limitations of the study?

This study does not explain why pioglitazone has better effects on people's cholesterol and fat in the blood than rosiglitazone does. It also does not look at whether the neutral effects of pioglitazone on these factors are enough to prevent heart and blood vessel problems.

What are the implications of the study?

Thiazolidinediones help control blood glucose in patients with type 2 diabetes, but they also cause some patients to gain weight. Pioglitazone is better at leveling a person’s cholesterol than rosiglitazone, which might help reduce the chance of developing heart and blood vessel problems.

Patients with diabetes should discuss with their doctors which diabetes medication is best for them.