People with diabetes don’t produce enough insulin to process the sugars in food they eat. If they don’t manage their blood sugar levels on a daily basis through diet, exercise or medication, excess sugar molecules can build up and attach themselves to red blood cells. And that can be a problem over time. Chronically high blood sugars put a diabetic at risk for complications affecting the eyes, kidneys and cardiovascular system.
The hemoglobin A1C is a blood test that measures the percentage of red blood cells that have these extra sugar molecules over a three-month period. It’s essentially a golf handicap for diabetics: the lower the number, the better job they’re doing managing the disease.
For the past decade, the American Diabetes Association (ADA) has recommended that the A1C goal for most diabetics should be less than seven percent. But the appropriate target can vary depending on a person’s age, how long they’ve had diabetes and what other health problems they have.
Researchers at the University of Chicago Medicine recently studied these recommendations to see how many diabetics really should keep their A1C below seven percent, and whether or not it makes sense to develop more personalized goals.
Neda Laiteerapong, MD, instructor of medicine, said, “We’re finding out more and more that people are just different in terms of when they develop diabetes and what it means for their lives.” In a study published in Diabetes Care, she and her colleagues assigned individual A1C targets to a nationally representative sample of US adults with diabetes, based on duration of the disease, age, diabetes-related complications and other health conditions. Given all these factors, they found that about half of US adults with diabetes should have an individualized A1C target higher than the ADA-recommended seven percent.
But if the goal is to keep the A1C as low as possible, what’s wrong with being a little ambitious? Laiteerapong said that more aggressive A1C targets don’t make sense for every patient.
“If you just developed diabetes, or you’re within 5 years or so of your initial diagnosis and you don’t have complications of diabetes, you probably should have very tight blood sugar control, less than 6.5 percent,” she said. “But for people who are older and have had diabetes for more than 10 years, or have complications from their diabetes, we don’t know if there’s a benefit from tight blood sugar control. There might be harm from it.”
The chances of developing one of these complications increases the longer a person has diabetes, as the effects of those high blood glucose levels accumulate. So it’s more important for a younger person with no complications to shoot for an A1C as low as they can tolerate.
On the other hand, low blood sugar, or hypoglycemia, can make a person feel disoriented, dizzy and light-headed, or in extreme cases even pass out or go into a coma. Medications for type 2 diabetes can also cause nausea, kidney damage or weight gain. For older patients with diabetes who may have already developed complications of the disease, the risk of having an extremely low blood sugar and injuring themselves, or suffering from the side effects of medications, just aren’t worth the benefits of more aggressive blood sugar control.
“We’re actually saying a minority of people should have an A1C less than seven percent, because most people fall into the exception category,” Laiteerapong said.
Other influential organizations such as the Veterans Administration and the American Association for Clinical Endocrinologists provide individualized recommendations for A1C targets, and the ADA does as well. The problem, Laiteerapong said, is that the seven percent number tends to be used as the benchmark that may not be applicable to everyone.
“The messages are mixed. They’re saying that most people should have this A1C target [of less than seven percent], and the few exceptions should have the individualized target,” she said. “But if we say things have to be individualized, it becomes very murky. How do you know someone’s actually doing a good job [managing their blood sugar levels]? It’s much easier to set a number and say that’s what it is.”
Laiteerapong and her colleagues hope that groups like the ADA, VA and others will take their findings into consideration when developing new guidelines. She also thinks the advent of electronic health records that can easily calculate individualized targets will help doctors develop realistic goals for their diabetic patients.
“We’re not saying that everyone should get less treatment. If patients are tolerating the medicines and want to be treated to a lower level of A1C, it’s probably fine,” she said. “But to say that everyone should be at one level is probably a little too simple.”
Laiteerapong N, John PM, Nathan AG, & Huang ES (2012). Public Health Implications of Recommendations to Individualize Glycemic Targets in Adults With Diabetes. Diabetes care PMID: 22961575