For Leigh Perreault, MD, an endocrinologist and associate professor of medicine at the University of Colorado Denver School of Medicine, who studies how to prevent type 2 diabetes, the answer is yes: clinicians should treat prediabetes more aggressively.
While prediabetes affects about a third of the U.S. adult population, using drugs to treat the condition remains rare. A recent report in Diabetes Care on the utilization of metformin, for example, shows that only .7% of people with prediabetes receive the drug.1
But for Dr. Perreault, metformin is “always a conversation” for her patients with prediabetes.
“After excluding other causes that might be prompting a jump in their glucose, I believe that the drug should be part of the treatment,” she says.
While the guidelines for diagnosing prediabetes have shifted over the years, the ADA currently classifies people with a hemoglobin A1C reading—the average blood sugar levels over 2 to 3 months—of 5.7 to 6.4%.
Without lifestyle changes to improve their health, it is estimated that 15 to 30% of people with prediabetes will transition to type 2 diabetes within five years. Diet and exercise can reduce that chance by 58% while metformin can cut the risk by 31% according to the Diabetes Prevention Program Outcomes Study. 2
“Of course, there are people who disagree, who say that that drug treatment is too widespread, too expensive, and has too many side effects,” says Dr. Perreault. “And that some people with an A1C of 6 won’t develop diabetes. But by prescribing metformin we can address issues earlier and help a lot of people.”
At present, metformin and other, newer, diabetes drugs have not been approved by the FDA for prediabetes care and are not covered by insurance.
But, Mark Schutta, MD, the medical director of the Penn Rodebaugh Diabetes Center at the University of Pennsylvania, notes that generic versions of metformin at Walgreen’s or Shoprite run about three dollars for a month’s supply.
“There are ways to get metformin if you really want to,” he says.
Metformin has been shown to be very benign and can help people lose a little weight. A study recently published in JAMA showed no significant risks associated with taking the drug.3
Given the benefits of metformin, why is it not prescribed more often for prediabetes?
Dr. Schutta speculates that many of his patients come through primary care or clinics where they’ve been screened, where the “level of understanding just isn’t there.”
“I routinely have patients with new-onset type 2 diabetes who were told five years ago that they had a high risk of developing type 2 diabetes and nobody did anything,” he says. “On the other hand, I see patients with prediabetes on GLP-1s such as Victoza and Trulicity as well as DPP-4’s and SGLT2’s. It’s like the Wild West out there….
While Dr. Perreault notes that people can develop familiar diabetes complications with prediabetes such as retinopathy or neuropathy, Dr. Schutta says these are “incredibly uncommon.”
The biggest risks, he says, are cardiovascular.
“As fasting glucose and A1C goes up in large cohorts of patients, risks of cardiovascular disease increases,” says Dr. Schutta. “People with prediabetes have one to two times higher the risk of cardiovascular problems than people without glycemic problems.” He points out that it’s not uncommon for patients who have had a heart attack, stroke, or even angina to discover that they have diabetes or prediabetes.
Both doctors recommend lifestyle changes to patients with prediabetes who are overweight and don’t exercise.
“I always talk to patients first about their lifestyle, explain the risks and discuss metformin and weight loss medications if appropriate. While I can’t always utilize some of the newer drugs that we use for diabetes, I would be predisposed to use them in certain cases if I could,” says Dr. Perreault.
“In a way, people who are overweight and don’t exercise are at an advantage with prediabetes,” says Dr. Schutta. “We know that if they diet and exercise they will improve their A1C and lower their risk for diabetes, while for those who already exercising and are at a reasonable weight, it can be a little more challenging.”
Yet while lifestyle changes in diet and exercise can go a long way in reducing the chances of transitioning from prediabetes to type 2, Dr. Perreault sometimes feels such physician advice isn’t enough.
“Patients are often told to go home, eat less and exercise more,” she notes. “But if they knew how to do that, wouldn’t they have already done it?”
To better address prediabetes, Dr. Perreault suggests lowering the threshold for a type 2 diagnosis.
“Maybe we should set the diagnosis for type 2 diabetes at an A1C of 6, and get rid of prediabetes,” she says. “That would mean more treatment, more diagnosis, and fewer complications. Plus then you could prescribe and pay for newer drugs.”
While saying that this idea intuitively makes sense, Dr. Schutta notes that individual cases vary, including patients who may not want to add drugs to their regimen.
“Part of our job is to individualize care, and determine what is most effective for a particular person. If a patient is willing to lose 8% of their weight through dietary changes and exercise, they often lower their A1C’s and risk of developing type 2’s significantly.”
“But if they’re not willing to do that, then you have to do something else.”