Despite metformin’s benefits for prediabetes, Rx rates lag

Timothy M. Smith , Contributing News Writer

More than one in three U.S. adults has prediabetes. That’s 96 million people who are at risk of developing diabetes, which already affects some 15% of the U.S. adult population. One potential preventive intervention is metformin therapy, which is economically feasible and identified by national clinical recommendations as effective. But is anyone prescribing it?

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For a study published in The Journal of the American Board of Family Medicine, researchers looked at metformin prescription rates in a national sample of commercially insured, higher-risk patients with prediabetes. While they found that prescription rates for higher-risk patients did rise at the one-year and three-year marks following a prediabetes diagnosis, the gains were modest—and rates remained low.

Timely interventions, the study’s authors wrote, are “critically needed.”

“Studies show that lifestyle change is vitally important for patients with prediabetes, and it's even more effective than metformin,” said Tamkeen Khan, PhD, a senior economist at the AMA who co-wrote the study.

The National Diabetes Prevention Program (National DPP) is a Centers for Disease Control and Prevention-approved lifestyle change program whose goal is to reduce the risk of type 2 diabetes.

“But lifestyle change is hard,” Khan said. “We thought it would be interesting to see whether metformin is being utilized at a meaningful rate for patients with prediabetes.”

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Using data on more than 50,000 patients with prediabetes from the IBM MarketScan research database between 2012 and 2018, the researchers examined metformin prescription rates one and three years after a laboratory confirmation of prediabetes among patients who had a body mass index (BMI) of 35 or greater or were younger than 60.

Overall, just 2.4% of patients received a metformin prescription within one year of a laboratory confirmed prediabetes result. For patients under 60, the number was the same, although the prescription rate was more than four times higher, 10.4%, for those with a BMI of 35 or greater.

By the third year, the overall metformin prescription rate climbed to 4.1%. The rate for patients under 60 also grew, although not as much, to 3.9%. Patients with a BMI of 35 or greater saw the biggest gains, with a prescription rate of 14%.

The AMA Diabetes Prevention Guide supports physicians and health care organizations in defining and implementing evidence-based diabetes prevention strategies. This comprehensive and customized approach helps clinical practices and health care organizations identify patients with prediabetes and manage the risk of developing type 2 diabetes, including referring patients at risk to a National Diabetes Prevention Program lifestyle-change program based on their individual needs.

“Clinical recommendations for prediabetes treatment specify that patients with prediabetes should be offered effective prevention interventions to prevent or delay progression to type 2 diabetes,” the authors wrote. “Our results demonstrate the lack of utilization of one such prevention intervention of metformin therapy."

The observed low prescription rates could be due to a number of barriers experienced in clinical encounters, including the limited time available with patients and the challenges of managing multiple chronic conditions, they added.

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“Our study shows this practice has changed very little in real-world settings up to 2018,” they wrote. “Since the annual progression rate from prediabetes to type 2 diabetes can be as high as 11% in certain populations, these delays represent missed opportunities to delay or prevent progression to type 2 diabetes among adults who are at higher risk.”

Previous studies that looked at metformin prescriptions also found low prescribing rates, the authors noted.

“Metformin and medical nutrition therapy is another alternative if patients are unable to commit to the National DPP,” Khan said, noting that metformin prescription rates do not need to be high if patients are getting one of the other interventions. “What’s most important is helping patients  keep their blood-glucose levels under control so they don't go into diabetes land. Because once they go there, it's a whole other ballgame.”