What’s the appropriate blood-sugar target for patients with Type 2 diabetes?
The debate heated up on March 6, when a prominent medical association advised relaxing the standard, saying that more aggressive targets can harm patients.
The source of the dispute: the hemoglobin A1C test, a test that measures a patient’s average blood-sugar, or glucose, levels. Glucose attaches to hemoglobin, a protein in red blood cells that carries oxygen.
The American College of Physicians concluded that most Type 2 diabetic patients’ A1C levels should be 7% to 8%. The group, which based its recommendation on a review of existing guidelines and clinical trials, published its guidance statement in the Annals of Internal Medicine.
The American Association of Clinical Endocrinologists, American Diabetes Association and other groups were quick to criticize the ACP’s new target as too high. They recommend setting A1C targets at 7% or lower.
Nearly 30 million people in the U.S. have Type 2 diabetes, a condition where blood-sugar levels become higher than normal because the body becomes resistant to insulin. Patients typically take insulin, metformin, sulfonylureas or newer, more expensive medications, including SGLT2 inhibitors, to control their blood sugar. Type 2 diabetes generally affects middle-aged and elderly people.
(Type 1 diabetes is an autoimmune condition usually diagnosed in children in which the pancreas stops producing insulin. The guidelines don’t affect those patients.)
Diabetes is a leading cause of death in the U.S. It can also cause heart disease, kidney failure and blindness.
“For most patients, an A1C between 7 and 8 seems to be the right spot where you maximize benefit and minimize burden,” says Jack Ende, president of the doctors group issuing the new guidelines and an internist at the University of Pennsylvania.
Dr. Ende says the burdens of striving for a lower number include a greater risk of low blood sugar, which can cause fainting. Patients taking medication to reach a lower A1C level may face side effects and weight gain. Studies have found that the more aggressive treatment of diabetes didn’t reduce deaths or complications, including heart attacks or strokes, he says.
One large, controlled trial of more than 10,000 Type 2 patients ended 18 months early. The patients in the group receiving intense therapy achieved a median A1C level of 6.4% but experienced increased rates of death and heart attacks compared with those undergoing a less intense treatment with a higher A1C target. Dr. Ende says this demonstrates that aiming for an A1C level below 7.0 isn’t appropriate. A 2008 study found no reductions in vascular complications in diabetic patients receiving stronger treatments.
Dr. Ende says there’s no harm in patients striving for lower A1C levels if they can reach them through lifestyle changes, such as diet and exercise. “It’s the excessive medication that can be problematic,” he says.
Patient confusion over varying guidelines, as well as the introduction of several new, costly medications that aim to lower a patient’s A1C, prompted the review.
Diabetes specialty groups have been quick to criticize the guidelines.
“We have big concerns about trying to lower the bar, so to speak,” says Jonathan Leffert, president of the American Association of Clinical Endocrinologists and a partner at the North Texas Endocrine Center in Dallas.
“There is a lot of data to support the fact that lowering A1C levels is beneficial, particularly in younger patients with Type 2 diabetes who have a lifelong potential of complications from diabetes,” he says.
Studies show that diabetes medications reduce the risk of a patient developing heart disease. They’ve also found that a lower A1C level decreases the risk of other complications, including nerve damage, he says.
“We say 6.5% for patients who are able to be intensively treated,” Dr. Leffert says. “That doesn’t mean that every patient should be at 6.5.”
William Cefalu, chief scientific medical and mission officer for American Diabetes Association, an Arlington, Va.-based group representing patients and professionals, says his organization’s guidelines will continue to recommend a target A1C level of 7%, with room for individualized therapy.
He notes that the studies supporting more aggressive treatment included older patients at high risk for developing heart disease. Studies with younger, newly diagnosed patients have found a lower rate of complications.
Write to Sumathi Reddy at [email protected]