A follow-up to a landmark diabetes study confirms that even after 10 years, intensive lifestyle modification can prevent or delay development of the disease among high-risk adults.
Furthermore, although physical activity and lifestyle change remain the surest way to prevent type 2 diabetes, when metformin was combined with some lifestyle intervention strategies, it performed as well as did intensive lifestyle interventions alone in reducing diabetes mellitus incidence.
The new study, the Diabetes Prevention Program Outcomes Study (DPPOS) is a follow-up to the 2002 Diabetes Prevention Program (DPP) trial. That study randomized adults at high risk for diabetes to an intensive lifestyle intervention, to 850 mg of metformin twice daily, or to placebo. High risk was indicated by raised fasting plasma glucose levels, impaired glucose tolerance, or a high body mass index (24 kg/m
After nearly 3 years, the incidence of diabetes was found to be 4.8 cases per 100 person-years in the lifestyle group and 7.8 cases in the metformin group, compared with 11.0 cases per 100 person-years among the controls.
The current study, led by Dr. William C. Knowler of the National Institute of Diabetes and Digestive and Kidney Diseases, followed up on 2,766 of these patients from the original 3,150 DPP participants for an additional 7 years, with about 900 patients coming from each of the three original cohorts.
This time, all three groups were offered lifestyle intervention, which encouraged 150 minutes of moderate-intensity activity per week and offered behavior reinforcement counseling sessions every 3 months. Patients who were in the lifestyle group in the original study also received two extra group classes “to reinvigorate their self-management behaviors for weight loss,” the authors wrote, and patients who were originally in the metformin-only group continued on their dose of 850 mg twice daily in addition to the lifestyle intervention.
The primary outcome—just as in the original study—was a fasting plasma glucose level of 7.0 mmol/L (126 mg/dL) or higher, measured every 6 months, or a 2-hour plasma glucose level of 11.1 mmol/L (about 200 mg/dL) or higher after a 75-g oral glucose load, measured yearly.
At the current study's end, roughly 10 years from patients' randomization into the original DPP, the combined incidence of diabetes (throughout both the original and current study periods) was 4.9 per 100 person-years for patients who received metformin plus lifestyle intervention, and 5.6 per 100 person-years among patients who had originally received only placebo but now received lifestyle intervention. The incidence of diabetes was 5.9 cases per 100 person-years among those who continued on the lifestyle-only intervention to which they had originally been assigned (Lancet 2009 Oct. 29 [doi:10.1016/S0140-6736(09)61457-4]).
“These results clearly advance our reasons to make lifestyle intervention a high priority for people who are at high risk for type 2 diabetes,” said Dr. R. Paul Robertson, the American Diabetes Association's president of medicine and science.
“It is our hope that health care professionals will translate the findings of this study to further motivate patients to make changes in their diet and physical activity to lower their risk,” he added.
A second phase of the follow-up, scheduled to be completed in 2014, will examine longer-term outcomes such as mortality.
Dr. Knowler and coauthors in the DPP research group declared that they had no conflicts of interest related to this study, which was funded by the National Institute of Diabetes and Digestive and Kidney Diseases. The ADA provided research funding support to the DPP and DPPOS.
The incidence of diabetes was 5.9 cases per 100 person-years in those who stayed on the lifestyle-only intervention.
Source Dr. Knowler