Glucose Testing: After Meals?
Should diabetics test their blood sugars after eating, too? The debate continues.
The Problems continued...
"I think that the recent attention to postprandial glycemia is a distraction," says David M. Nathan, MD, director of the diabetes center at Massachusetts General Hospital and a professor of medicine at Harvard Medical School. "In general, postprandial glycemia, fasting glycemia, and chronic glycemia, as measured by the A1c test are highly correlated. Attention should just be focused on overall lower glycemia."
Nathan points to the biggest problem with the postprandial hyperglycemia hypothesis. While epidemiological research has suggested a connection between postprandial hyperglycemia and diabetic complications, this sort of research looks at a large number of variables and isn't designed to test postprandial hyperglycemia specifically. There isn't yet a method to single out the particular effects of postprandial hyperglycemia from other common risk factors like hyperglycemia, obesity, and hypertension. As a result, there's no way to know if postprandial glucose levels really matter on their own.
"I just don't think postprandial testing is worth putting energy into now, because if you look for other risk factors of diabetes, you will find all of these people anyway," says David E. Goldstein, MD, principal investigator from the health sciences center at the University of Missouri School of Medicine. "There just isn't evidence that postprandial glucose levels matter independent of other factors, like A1c."
"But it's a hot topic now, though," Goldstein says wearily. "It's a snake pit, or a bottomless pit. I don't know what to call it."
Detecting and Treating Postprandial Hyperglycemia
While the significance of postprandial testing and the standards for doing it haven't been firmly established, proponents like Goldstein and Ganda ask their patients to keep a log of blood sugars before and after a certain meal each day for a few weeks before a doctor's visit; that way, they can see whether there are any worrying spikes in the glucose levels above 140 mg/dL.
Treatment for postprandial hyperglycemia can include behavioral techniques such as exercise and weight loss, and medication. One ongoing study, the European Study to Prevent Non-Insulin Dependent Diabetes (STOP-NIDDM), seems to show that treatment of people with IGT -- based on postprandial blood sugars -- with the drug acarbose (Precose or Prandase) helped prevent the onset of type 2 diabetes and reduced the risks of cardiovascular problems. In his practice, Goldstein has had success using sulfonylureas and fast-acting insulins in reducing postprandial blood sugar levels.