Hemoglobin A1C is a number that indicates your average blood sugar for the previous two to three months. If you have a hemoglobin A1C of 5.7 to 6.4 percent, you have prediabetes. If your hemoglobin A1C is 6.5 percent or higher, you have diabetes. Doctors often also use a fasting blood glucose test to determine if you have diabetes; a result of 126 milligrams per deciliter or above indicates diabetes, and 100 to 125 mg/dL indicates prediabetes.
Generally speaking, once you develop diabetes, doctors will want you to maintain an average hemoglobin A1C of 6.5 percent to 7 percent. Those numbers are recommended by large groups of professionals within diabetes, such as the American Association of Clinical Endocrinologists (6.5 percent) and the American Diabetes Association (7 percent).
But just how were these target hemoglobin A1C numbers established for prediabetes and diabetes — and are they really the best target numbers for you?
[Read: 11 Tips for Testing Your Blood Sugar at Home.]
The answer varies for each person, says Dr. Robert Gabbay, chief medical officer and vice president at the Joslin Diabetes Center, which is part of Harvard Medical School in Boston.
First, let’s look at the A1C numbers that indicate prediabetes and diabetes. Tests such as fasting blood glucose and a two-hour oral glucose tolerance test have long histories as diabetes tests, Gabbay says. Hemoglobin A1C became more closely associated with the diagnosis of prediabetes and Type 2 diabetes more recently after experts from the ADA, the European Association for the Study of Diabetes and the International Diabetes Federation came together and published a target A1C goal and shared other patient recommendations, says Dr. Rachele Berria, head of the U.S. Diabetes Medical Unit for the drug company Sanofi. “These [hemoglobin A1C] numbers are important because they let health care professionals know how a person living with diabetes is doing, and what impact food, exercise and medications have on a patient’s blood sugar,” Berria says.
When someone has A1C results in the 5.7 to 6.4 percent range — or prediabetes — they have a chance to make life changes so they won’t develop full-blown diabetes. “There is more of an emphasis now on preventive care and making sure patients with prediabetes get on top of diet and exercise and, if obese, even consider metformin therapy, because we know that cardiovascular disease risk begins even with prediabetes,” says Dr. Valentina Rodriguez, an endocrinologist with the Division of Endocrinology, Diabetes, & Metabolism at the NYU School of Medicine in New York.
[See: 6 Tips to Keep Diabetics Out of the Hospital.]
Then there’s the target hemoglobin A1C goal of 6.5 or 7 percent when you have diabetes. The reason for patients to meet their goal number consistently is to help avoid eye, nerve, kidney and other health problems that arise when blood sugars are consistently high, Gabbay says. However, “the reality is that there’s not a hard cutoff point,” he says. And there was controversy when the AACE began to push for the 6.5 percent goal, Gabbay adds.
The specific hemoglobin A1C goal for each patient can vary based on age, other medical conditions including kidney disease and your individual risk for hypoglycemia (low blood sugar). For instance, a doctor may suggest that a younger patient aim for 6.5 percent, while an older patient with heart disease may have a goal closer to 8 percent. Low blood sugar is more dangerous in patients with heart disease.
“As a general rule in my practice, in patients older than 70, I use their decade to guide me,” says Dr. Lorena Lewy-Alterbaum, an endocrinologist with Memorial Regional Hospital South and in private practice in Hollywood, Florida. “For a 75-year-old, the [A1C goal] would be 7.5 percent, and for an 80-year-old, it’s up to 8 percent. In these age groups, the concern is towards prevention of hypoglycemia as much as diabetes control.”
In some patients, there are other problems associated with lowering a blood sugar too much, including medication overuse and the side effects and costs associated with those medications, Alterbaum says.
It’s important to know what your target hemoglobin A1C should be — and to let your care team know what efforts you’ll make to lower your blood sugar. That’s because a survey from the AACE and Sanofi found that patients are more willing to take action to reach A1C targets than their health professionals believe, Berria says. “Those differing perceptions could play a role in the length of time it takes some patients to achieve their individualized A1C targets,” she says.
Despite that self-motivation from patients, it’s estimated that about 50 percent of adults living with diabetes still do not meet their target numbers, Berria says.
The AACE recommends that patients be re-evaluated every three months to aim for early prevention against dangerous blood sugar trends, Berria says.
One factor that doctors consider more these days is the importance of consistent blood sugar levels. “An A1C is just an average. If someone has several episodes of hypoglycemia, this is dangerous but may make the A1C appear well-controlled at 6.5 percent, for example. Similarly, for some patients with hemoglobin disorders, an A1C may not be the most reliable measure as this could be falsely elevated or falsely low,” Rodriguez says.
[See: The 12 Best Diets to Prevent and Manage Diabetes.]
“Many patients feel terrible when their blood sugars are all over the place,” Gabbay says.
Some doctors find that the use of continuous glucose monitoring devices help patients assess their blood sugar more consistently than just by use of the hemoglobin A1C test.
Diabetes organizations and researchers continue to refine the target numbers for people living with diabetes. Some recent research has focused on blood sugar control in people with diabetes and heart disease. In fact, two large trials called ACCORD and ADVANCE did not show a decrease in heart disease with stricter blood sugar control goals of 6 to 6.5 percent. “So, it seems that again, each patient has to be evaluated and individualized based on their age, health status and comorbidities,” Alterbaum says. Comorbidities are chronic health conditions that a person has at the same time.
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Why Hemoglobin A1C Numbers Are Important for Your Diabetes originally appeared on usnews.com
