In this national survey, we found substantial gaps in PCP knowledge of risk factors, diagnostic criteria, and evidence-based recommendations for prediabetes. Importantly, PCPs identified both patient- and system-level barriers to and facilitators for diabetes prevention in primary care. To our knowledge, this is the first national survey to evaluate PCP knowledge and practices related to prediabetes. Understanding prediabetes management in primary care is important as the national landscape for type 2 diabetes prevention is evolving rapidly.

Inadequate PCP knowledge of risk factors, diagnostic criteria, and screening tests likely lead to underscreening of at-risk individuals and low rates of identification of patients with prediabetes. National CDC data support this finding as nearly 90% of persons with laboratory values consistent with prediabetes are unaware of their status.1 Our results also suggest that 25% of PCPs may be identifying people as having prediabetes when they actually have diabetes which could lead to delays in diabetes-specific preventive care. One-fourth of PCPs reported using a non-fasting glucose for prediabetes screening even though no such diagnostic criteria exist.

We also found low knowledge and implementation of evidence-based recommendations for prediabetes, specifically the referral of patients to diabetes prevention lifestyle programs. PCPs most commonly recommend 10% weight loss to their patients with prediabetes, but evidence suggests that lower thresholds (5–7%) are sufficient for achieving clinical benefits.17, 19, 20 Knowledge of this lower weight loss target is essential for providing patients achievable goals. Competing demands, including the need to meet quality metrics and maintain patient volume, may limit providers’ ability to stay current with evidence for prediabetes; therefore, in addition to systematic education efforts for PCPs, expanding other team members’ roles and clinical decision support may improve prediabetes identification and management.

Consistent with prior literature,21, 22 PCPs reported significant patient barriers to managing prediabetes, including a lack of motivation. Identifying and discussing the diagnosis of prediabetes with a patient may be a salient moment for PCPs to motivate patients to make lifestyle changes; prior studies have demonstrated the important role that PCPs play in motivating patients to make lifestyle change.23,24,25,26 PCPs identified other patient barriers to lifestyle change including stress, limited time, and constrained resources; the diabetes prevention lifestyle change program is grounded in effective behavioral intervention methodology focusing on incremental changes in health behaviors and these important life factors.19

PCPs identified patients’ dislike of taking medications, poor adherence, and potential side effects as barriers to metformin use. A recent study showed that patients with diabetes risk factors felt that lifestyle intervention and metformin were both acceptable treatment options for prediabetes39 with some wanting to combine modalities. Therefore, physicians’ perceived barriers, including patients’ reluctance to take medication, may be incorrect. Our results showing lower PCP knowledge about metformin’s effectiveness in diabetes prevention may influence practice behaviors around prescribing metformin. Recent studies show that < 1% of patients with prediabetes are on metformin.12, 13, 27

PCPs identified a lack of weight loss resources for patients as an important system-level barrier. The number of CDC-recognized organizations delivering the National DPP lifestyle change program is growing rapidly and is now available in every state,28 but may not be widely available and accessible. There is ongoing effort by multiple stakeholders to increase the availability of the National DPP lifestyle change program. The AMA is working closely with practices and health systems to deliver these programs to their patients or to help connect them to local CDC-recognized organizations.29 Online programs may help address accessibility issues. If local programs are unavailable, resources like registered dietitians can be utilized although may not be covered by all insurers, and educational materials (e.g., through the National Diabetes Education Program) can be provided to at-risk individuals.30, 31 Other non-CDC-recognized diabetes prevention lifestyle programs may be available, but they may not have the long-term evidence or outcomes that CDC-recognized programs have and may not be covered by insurance.

Most PCPs strongly believe that system-level interventions for improving the management of prediabetes should include increasing insurance coverage of and coordinated referral to National DPP lifestyle change programs. Coverage of these programs (in-person and online) is expanding, beginning with commercial insurers and now with CMS.7 Increasing physician education about the evidence behind diabetes prevention and having a direct referral mechanism for nearby National DPP lifestyle change programs would likely improve referral rates. Ultimately, this requires integration of community-based National DPP lifestyle change programs into electronic referral workflows. Other improvements such as clinical decision support tools have been shown to improve processes of care for diabetes and other illnesses32, 33 and may be effective for the diagnosis and management of prediabetes.

Strengths of this study include its national coverage of PCPs in a variety of practice settings and the comprehensive nature of the survey. The major limitation to this study is the relatively low response rate which may limit the generalizability of our results; however, our response rate is comparable to other surveys of the AMA Masterfile sample to understand PCP knowledge, attitudes, and practices.34, 35 Respondents were similar to the national PCP population for most demographic characteristics, including gender, race/ethnicity, and practice setting.36, 37 However, respondents were generally older than the national PCP population (62% vs. 25% were aged 60 and older).37 We used the term “diabetes prevention lifestyle program” when asking PCPs about management approaches to avoid leading respondents in their responses, but PCPs may have selected this management option without meaning the structured behavioral weight loss program in the DPP study. Therefore, our estimate that one-third of PCPs recommend their patients with prediabetes to a diabetes prevention lifestyle program may overestimate the referral rate. There may be recall bias (unmotivated misreporting) regarding physician practices38 and social desirability bias (motivated misreporting in a socially desirable direction) in responding to questions about perceived barriers and practices, leading to more positive agreement about the importance of prediabetes.38

Our national survey findings suggest that gaps in PCP knowledge contribute to the inadequate diagnosis of prediabetes and referral to diabetes prevention interventions. In addition to provider education, addressing system-level barriers to type 2 diabetes prevention is important and will require partnerships with community resources and leveraging of health information technology. PCPs play a critical role in identifying and treating the one in three adults with prediabetes. As type 2 diabetes prevention grows through dissemination of evidence-based interventions, increased engagement of PCPs is the next step to addressing the diabetes epidemic.