INTRODUCTION

Type 2 diabetes is a major public health challenge but can be prevented. The landmark Diabetes Prevention Program (DPP) Trial demonstrated a 58% reduction in 3-year diabetes incidence with an intensive lifestyle intervention in high-risk persons with prediabetes.1 There is substantial interest in translating this program to community settings. In 2010, the Centers for Disease Control and Prevention created a partnership called the National Diabetes Prevention Program (National DPP) and developed a set of guidance documents and steps for national certification of local lifestyle change programs.2 In 2018, the Centers for Medicare and Medicaid Services began providing insurance coverage for Medicare beneficiaries meeting Medicare DPP criteria to attend recognized DPPs.3 As is typical for research translation, community-based programs that are part of the National DPP use less restrictive eligibility criteria than the original DPP Trial. The Medicare DPP model was certified based on expected Medicare savings.4 Differences in eligibility criteria may influence the effectiveness of the intervention and the potential influence on the diabetes epidemic. Currently, it is unknown how many adults in the USA are eligible for these programs. By each set of criteria, we sought to quantify (1) the proportion and number of US adults who would be eligible and (2) the differences in characteristics of adults identified.

METHODS

We conducted a cross-sectional descriptive analysis of adults aged 20 years or older who participated in the 2007–2016 National Health and Nutrition Examination Survey (NHANES) (n = 8792). We determined the proportion of the non-diabetic US population eligible for each program and compared clinical characteristics. Analyses were conducted in 2018, accounted for the complex survey design, and were weighted to the 2016 US adult population. National DPP eligibility criteria are age ≥ 18 years, BMI ≥ 25 kg/m2 (Asian ≥ 23 kg/m2), and any one of the following: HbA1c 5.7–6.4%, fasting glucose 100–125 mg/dL, 2-h glucose 140–199 mg/dL, history of gestational diabetes, or CDC Prediabetes Risk Score ≥ 9.3 Medicare DPP eligibility criteria are age ≥ 65 years, BMI ≥ 25 kg/m2 (Asian ≥ 23 kg/m2), and any one of the following: HbA1c 5.7–6.4%, fasting glucose 110–125 mg/dL, or 2-h glucose 140–199 mg/dL.2 DPP Trial eligibility criteria are age ≥ 25 years, BMI ≥ 24 kg/m2 (Asian ≥ 22 kg/m2), fasting glucose 95–125 mg/dL, and 2-h glucose 140–199 mg/dL.1

RESULTS

Overall, 101.2 million US adults (47.7%) were eligible for National DPP in 2016, corresponding to 43.5% of adults aged 20–64 and 69.4% of adults aged ≥ 65 years (Fig. 1). Among adults ≥ 65 years, 41.9% (15.3 million) were eligible for Medicare DPP. In contrast, 11.0% of adults aged 20–64 (19.1 million) and 30.2% of older adults (11.1 million) met eligibility criteria for the original DPP Trial.

Fig. 1
figure 1

Proportion and number of US adults aged ≥ 20 years meeting eligibility criteria for Diabetes Prevention Programs, stratified by age < 65 years and ≥ 65 years, NHANES 2007–2016. Standardized to the 2016 US adult population using the American Community Survey.

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Adults eligible for National DPP had more favorable risk factor profiles than those who would be eligible for the DPP Trial, as assessed by body mass index, lipids, blood pressure, HbA1c, fasting glucose, and 2-h glucose (Table 1). Older adults eligible for National DPP but not Medicare DPP had a mean HbA1c of 5.3% and fasting glucose of 95 mg/dL (33% with prediabetes by ADA definition), whereas those eligible for Medicare DPP had a mean HbA1c of 5.7% and fasting glucose of 110 mg/dL (100% with prediabetes).

Table 1 Percent, Number, and Characteristics of US Adults by Diabetes Prevention Program Eligibility, Stratified by Age < 65 Years and ≥ 65 Years, NHANES 2007–2016
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DISCUSSION

Almost half of US adults met eligibility criteria for National or Medicare DPP. Adults eligible for these community-based programs represent very different populations—with more favorable cardiometabolic profiles—compared to the original participants of the DPP Trial. Our estimates provide useful information on the number of US adults eligible for these established programs but do not reflect program enrollment or account for eligibility restrictions such as life-limiting diseases or disability.

Older adults meeting National DPP but not Medicare DPP eligibility criteria were a lower-risk population, only 1/3 of whom had prediabetes. While weight loss interventions have multiple benefits, including improving blood pressure, cholesterol, mobility, and quality of life,5 DPP participation by high-risk, young and middle-aged adults may pay the greatest dividends for reducing long-term diabetes complications in the USA. Creating sustainable community-based programs will be challenging; there is growing interest in digital platforms to deliver these interventions.6 Ensuring access to recognized DPPs for high-risk individuals while simultaneously pursuing population-based prevention policies will be critical for reducing the burden of diabetes in the USA.