Glucose Testing: After Meals?
Should diabetics test their blood sugars after eating, too? The debate continues.
"I think postprandial testing is very important," says
Om Ganda, MD, director of the lipid clinic at the Joslin Diabetes Center and
associate clinical professor at Harvard Medical School. "In order to
control diabetes well, you need to control the blood sugars 24 hours a day, and
not just when you're fasting. People can have a pretty normal fasting blood
sugar but still have a high postprandial level."
While there haven't been a great number of studies of
postprandial hyperglycemia, there have been a number of suggestive studies of
something called post-challenge hyperglycemia. Post-challenge glucose tests are
administered after a person takes a set amount of glucose, usually 75 mg in a
liquid form. The precise relationship between post-challenge hyperglycemia and
postprandial hyperglycemia has not been firmly established, but proponents cite
a few studies that indicate a good correlation.
"There's a lot of epidemiological evidence coming from all
over the world suggesting that post-challenge blood sugars and thus
postprandial blood sugars have their own independent risks or at least greatly
augment understood risks," says Jellinger. "We thought that it was in
our patients' best interest to bring this issue to light."
Experts have been focusing an increasing amount of attention on
the cardiovascular risks of diabetes -- such as heart attack and stroke -- and
some epidemiological studies have suggested that postprandial hyperglycemia is
directly related to cardiovascular complications.
In addition, some suggest that postprandial testing may detect
people with impaired glucose tolerance (IGT) or impaired fasting glucose (IFG)
-- so-called "pre-diabetes" -- who might be missed by fasting
"Epidemiological evidence suggests that there are a lot of
people out there who don't have diabetes and who don't have pre-diabetes but
have abnormal postprandial glucose levels," Ganda tells WebMD. "And
based on a number of studies in the U.S. and Europe, they may be at an
increased risk of cardiovascular disease."
However, not everyone agrees that postprandial testing is so
important. No one debates that people with diabetes are more likely to have
postprandial glucose spikes -- or excursions -- than those without diabetes.
What is debated, and debated fiercely, is whether these spikes require any
specific treatment separate from typical care for diabetes.