Evidence Supporting Prevention

Status of prediabetes in the United States

  • An estimated 86 million U.S. adults have prediabetes.1
  • Adults with prediabetes are at risk for developing type 2 diabetes and cardiovascular disease.
  • Data from the National Health and Nutrition Examination Survey (NHANES) reported that during 2009–2010, approximately 11 percent of those with prediabetes were aware of their condition.2
  • NHANES data also show awareness of prediabetes was less than 14 percent in 2009–2010 regardless of education level, income level, coverage by health insurance or other health plan, or health care use.2

Evidence for prevention

  • In 2001, the National Institutes of Health’s Diabetes Prevention Program clearly demonstrated that type 2 diabetes could be delayed or prevented in those at risk for developing diabetes.3
    • In the DPP, diabetes incidence over a 3-year period was reduced by 58 percent in the lifestyle group as a whole and 31 percent in those taking metformin compared with the placebo group.3
    • DPP showed that losing a small amount of weight by following a low fat, low calorie meal plan and increasing physical activity lowered diabetes risk by 71 percent in participants age 60 and older.3
    • Metformin was most effective in younger (aged 25–44 years) and in heavier (body mass index ≥ 35 kg/m2) adults in the DPP study as well as in women with a history of gestational diabetes.3
    • Weight loss was the dominant predictor of reduced diabetes incidence. For every kilogram of weight loss, there was a 16 percent reduction in risk, adjusted for changes in diet and activity.4
    • Analysis of achievement of weight and activity goals showed that success increased with age and initial success predicted long-term success. Self-monitoring and meeting activity goals were related to achieving and sustaining weight loss.5
  • The NIH-sponsored Diabetes Prevention Program Outcomes Study (DPPOS), the follow-up study to the DPP, showed effects of the DPP have persisted:
    • The incidence of diabetes in the 10-year follow-up study was reduced by 34 percent in the lifestyle group and by 18 percent in those taking metformin compared with the placebo group.6 Because the placebo and lifestyle intervention groups were offered almost the same lifestyle intervention resources between years 4 and 10 of the DPP, these numbers likely underestimate the true benefit relative to usual care today.
    • For participants age 60 and older, the 10-year development of diabetes was reduced by 49 percent with intensive lifestyle changes aimed at modest weight loss when compared with placebo.6
    • Intensive lifestyle intervention can result in reductions in total energy intake for up to 9 years. Initial success in achieving reductions in fat and energy intake and success in attaining activity goals appear to predict long-term success at maintaining changes.7
    • The incidence of diabetes at 15 years was reduced by 27 percent in the lifestyle group and by 18 percent in metformin group compared with the placebo group.8
    • At 15 years, there were no overall differences in microvascular outcomes between treatment groups; however, those who did not develop diabetes had a lower prevalence of microvascular complications than those who did develop diabetes.8

Economic considerations of diabetes and its prevention

  • Interventions to prevent or delay type 2 diabetes in people with prediabetes are cost-effective versus placebo.9,10
  • Americans with diagnosed diabetes have annual medical expenditures that are $7,900, or approximately 2.3 times higher than they would be in the absence of diabetes ($13,700 vs. $5,800).11
  • The estimated annual cost of prediabetes in 2007 was $25 billion, or an additional $443 annually for each adult with the condition. People with prediabetes had 34 percent more ambulatory visits associated with their condition than the reference population, including 92 percent more visits for hypertension and 9 percent more visits for cardiovascular disease. This additional health care usage translated to an additional physician visit and two additional prescriptions per year for each person with diabetes.12
  • The total estimated cost of diagnosed diabetes in 2012 was $245 billion ($176 billion in direct medical costs and $69 billion in reduced productivity), representing a 41 percent increase from the 2007 estimate. The majority of direct medical costs, 59 percent, was for the population aged 65 years or older, who are primarily covered by Medicare insurance.11
  • As of 2014, 29.1 million Americans (9.3 percent) have diabetes1, and the lifetime risk of diagnosed diabetes is approximately 40 percent for adults.13 Associated costs and burden on the health care systems will increase accordingly as the number of Americans with diabetes continues to grow.


Last Reviewed October 2015