Did you know that diabetes medicines work differently for every patient?How your body responds to a medicine can depend on how long you have had diabetes, if you have other diseases, or whether you experience side effects from some of theingredients.But did you know that your sex can alsoeffect the way diabetes medicines work?Recent research has found that one diabetes drug, metformin, may have very different effects in men and women.

About type 2 diabetes

If you have type 2 diabetes, your blood glucose levels will be unhealthy for two reasons. First, while the pancreas (an organ close to the stomach) still makes insulin, it doesn’t make enough of it for your body’s needs. Second, the cells in your body do not deal well with the insulin that is produced, so they cannot make full use of the glucose in the blood stream. For reasons that are not completely understood, patients with type 2 diabetes have a higher risk of heart failure than people who do not have diabetes.

The research
The study looked at a group of 78 men and women who were given either:

• Metformin, which helps cells in the body use insulin better.
• Metformin and Avandia; Avandia helps the body use insulin better, but it also affects blood fat levels.
• Metformin and Lovaza; Lovaza is a fish oil tablet that is thought to lower triglyceride (a type of fat) levels in the blood.

The study found that when the patients were divided into men and women, blood glucose control was roughly the same for both.But, the drugs’ effects on the heart were very different for each group.

Unlike other studies that used blood tests to check cholesterol, and blood fat levels to check heart health, this study used “positron emission tomography,” or PET scans. PET scans measure blood flow to the heart, andhow well the heart uses oxygen. They also show how well the heart uses glucose and fats for energy. This is important, as other research has found that the heart is healthier when it can use glucose as its main source of energy, instead of fat.

The research results:

In women, metformin increased the amount of glucose used for energy by the heart, and reduced the amount of fat the heart used—this is a very good effect.In men, however, metformin worked the opposite way. The study showed that the heart used more fat and less glucose —this is a bad effect. In fact, for men, metformin made the heart less efficient at using glucose for energy.This means that taking metformin alone might be badfor a man’s heart.

So what are the main points to take away from this study?

• Metformin caused men’s hearts to burn less sugar and more fats for energy. This increases their risk for heart failure.
• If men took Avandia or Lovaza plus metformin, it helped reduce some of the bad effects of metformin on the heart.
• Metformin caused women’s hearts to use more sugar and less fat for energy. This is better for the heart.
• Taking metformin plus Avandia helped improve how the heart used glucose for energy in women. The results were better than with metformin alone.

So, what do these research results mean?

From earlier research, the researchers knew that women are healthiest when their hearts burn morefat for energy than glucose. The hearts of healthy men tend to use more glucose for fuel. This explains why women with diabetes are more at risk for heart failure than men: their hearts must rely even more on fat, which can damage the heart muscle.

If all women (with or without diabetes) have a higher risk of heart failure, this may explain why diabetes drugs seem to help women more than men.The medicines fix a problem in women that men don’t have. More studies are needed to find out exactly why these diabetes drugs work in different ways in men and women.

Take home message:

Some diabetes medicines can have different effects on men and women.Therefore, it is important to visit your healthcare provider often, so he or she can make sure the medicines you are taking will help your blood glucose without causing other problems.
Reviewed by Robert Ehrman, MD