Fifteen years ago, the landmark finding that a lifestyle intervention program could do a better job at preventing diabetes than taking metformin set in motion the creation of the National Diabetes Prevention Program (DPP), which will be funded by Medicare starting next spring.
The risk of developing type 2 diabetes can depend on a host of factors—from age, to activity level, to underlying clinical measures. So, there was an obvious question: while the DPP's success in a broad population was well-documented, what factors could predict its success for the individual patient?
Now, the Diabetes Prevention Program Research Group has tackled that topic in a study just published in Diabetes Care
, the journal of the American Diabetes Association.
What they found is encouraging for those who see lifestyle intervention, and especially the DPP, as a solution to America’s $245 billion annual tab for diabetes. In patients who stuck with the program, meaning those who had lost least 5% of body weight at 6 months, the lifestyle intervention worked well “regardless of baseline risk,” the authors wrote, and was “substantially more effective than metformin intervention in those at highest risk.”
More importantly, the study produced data across 19 specific clinical variables that can guide physicians and patients. In short, diabetes prevention could become customized.
“That is our hope,” William Herman, MD, of the University of Michigan, the study’s lead author, wrote in an email to The American Journal of Managed Care®
. “Our goal was to facilitate personalized decision-making.”
Among patients who adhered to their regimen, the study found:
The lowest-risk patients who took part in the lifestyle intervention had an 8% absolute risk reduction (ARR) of developing diabetes and a 35% absolute likelihood of reverting to normal glucose regulation (NGR), compared with placebo.
The highest-risk patients in the lifestyle group had a 39% ARR of developing diabetes and a 24% greater likelihood of reverting to NGR, compared with placebo.
The lowest-risk patients taking metformin had no reduction risk for developing diabetes, and a 17% greater likelihood of reverting to NGR. High-risk patients who took metformin had a 25% ARR of developing diabetes and an 11% greater likelihood of reverting to NGR.
Diabetes consumes $1 of every $3 in Medicare—a share that helped convince CMS to invest in DPP to turn the tide. The yearlong program has a CDC-approved curriculum of 16 weekly core sessions, followed by a maintenance period of monthly sessions. A 2002 study funded by the National Institutes of Health (NIH) found a 58% reduction in participants progressing to diabetes.
However, this new study confirms the biggest problem in prevention: adherence is really
hard, whether the person is taking a pill or trying to follow a healthier lifestyle. In recent years, multiple programs have emerged to offer the DPP—both through in-person and in online formats. Several digital health companies are embracing principles of behavioral science to simultaneously tackle the adherence and the behavioral change hurdles.
“The study reinforces even more clearly what the original DPP study by the NIH demonstrated: that behavioral interventions are more effective for those at risk for diabetes than is metformin; this is true across the baseline risk spectrum,” said Carolyn Jasik, MD, director of Medical Affairs at Omada Health. “For too long, the barrier to behavioral interventions being the actual standard of care was scalability, access, and personalization—that’s what Omada has come to the market to solve.”
How the Study Worked
The study tracked 19 clinical variables in 3234 patients who met the clinical criteria for prediabetes to enroll in the DPP. They were randomized into 3 groups: 1079 to do the lifestyle intervention, 1073 to take metformin, and 1082 to take placebo. Besides weight, body mass index, blood pressure, fasting plasma glucose, and triglycerides, variables included age, gender, race/ethnicity, education and income status, smoking status, physical activity levels, family history of diabetes, and polycystic ovary disease (among women).
The study also yielded data on whether each variable was associated with progressing to diabetes or returning to normal blood glucose regulation, and the answer could change depending on the study arm. Researchers found that 11 measures predicted a progression to diabetes, while 6 predicted a regression to normal glucose regulation, but only 3 were seen across all groups. For example, a male college graduate who had lower systolic blood pressure at baseline might be expected to return to NGR in the metformin group, but not in the placebo or lifestyle intervention group.
Herman explained the value of these findings. “Randomized, controlled trials like the Diabetes Prevention Program assess whether treatments work and report average benefit. We show that the benefit to an individual varies greatly, even within a seemingly homogenous study population.”
The hope, he said, is that the algorithms from the study will let patients assess their own likelihood to benefit from the prevention choices available, “and act accordingly.”
Adherence Is Still Hard
Only 62% of the lifestyle participants, 68% of the metformin participants, and 72% of the placebo participants could stick with their programs. However, the researchers found that those who could adhere to the lifestyle intervention were less likely to progress to T2D than those who consistently took metformin. (Medication adherence was defined as taking the drug or placebo at least 80% of the time.)
Herman said each person’s assessment of their ability to adhere to an intervention is critical. “The knowledge of the potential benefits of participating in a lifestyle or metformin intervention is important, but individuals must also weigh the feasibility of adhering to the intervention,” he said. “I think the takeaway point is that providers should support whichever course of action and individual thinks is best—recognizing that the choice may change over time.”
Herman WH, Pan Q, Edelstein SL, et al. Impact of lifestyle and metformin interventions on the risk and progression to diabetes and regression to normal glucose regulation in overweight or obese people with impaired glucose regulation [published online October 11, 2017]. Diabetes Care.