The Curbsiders podcast

#309 USPSTF Quick Update: Prediabetes & Type 2 Diabetes Screening

December 6, 2021 | By

With Dr. Chien-Wen Tseng


Sweeten your day with a review of the updated 2021 USPSTF Prediabetes and Type 2 Diabetes screening guidelines with expert guest Dr. Chien-Wen Tseng! We review the new screening recommendations, assess different testing modalities, talk through screening intervals, and emphasize other risk factors that impact screening! 

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  • Written and Produced by: Paul Williams MD & Elena Gibson MD
  • Cover Art: Beth Garbitelli
  • Hosts: Paul Williams MD, FACP; Elena Gibson MD    
  • Reviewer: USPSTF Team
  • Executive Producer: Beth Garbitelli
  • Showrunner: Matthew Watto MD, FACP
  • Editor: Clair Morgan of
  • Guest: Chien-Wen Tseng MD

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The Curbsiders are partnering with VCU Health Continuing Education to offer FREE continuing education credits for physicians and other healthcare professionals. Visit and search for this episode to claim credit. See info sheet for further directions. Note: A free VCU Health CloudCME account is required in order to seek credit.

Time Stamps*

*Note: Time Stamps refer to ad free version. 

  • Intro, disclaimer, guest bio: 0:33
  • Guest one-liner: 3:30
  • Picks of the Week: Sneaky pick at 3:00! Guest pick: 4:45
  • Case from Kashlak of Mr. Sugar: 5:30 
  • Screening recommendations: 6:00
  • Testing modalities: 10:00 
  • Possible harms of screening: 15:50
  • Screening intervals: 18:00
  • Prediabetes screening: 20:45
  • Other risk factors that impact screening: 26:30
  • Recap: 34:15
  • Outro: 36:25

USPSTF Update: Prediabetes & DM Screening Pearls

  1. The USPSTF recommends screening for prediabetes and Type 2 diabetes in adults ages 35 to 70 who have overweight or obesity.
  2. One of the biggest changes from the 2015 recommendation is lowering the age of screening initiation from 40 years old to 35 years old.
  3. Screening can be completed with one of the following: 1) Hemoglobin A1c 2) Fasting glucose 3) Glucose tolerance test. 
  4. If initial screening is normal, a reasonable interval for repeat screening is 3 years. 
  5. Screening should be considered at a lower BMI >23 for Asian American patients and at an earlier age if the patient is from a population with a disproportionately high prevalence of diabetes. 

USPSTF Update: Prediabetes & DM Screening 

Overall Recommendation

The USPSTF recommends screening for Prediabetes & Type 2 Diabetes in adults ages 35 to 70 years who have overweight (BMI > 25) or obesity (BMI > 30) (USPSTF 2021).  This is an update to a 2015 recommendation that advised screening initiation at age 40 in the same population.  “One of the main reasons we dropped the age to 35 is because we are really following the public health crisis,” Dr. Chien-Wen Tseng said. “The rates of diabetes have really increased over the last ten years.” 

Supporting Evidence

In the United States, approximately 88 million American adults—more than 1 in 3—have prediabetes (CDC) and diabetes is the seventh leading cause of death in adults (Heron, 2017, ADA). One of the main reasons the age of screening initiation was changed to 35 is evidence that the incidence of prediabetes/diabetes increases at this age (Jonas et al, 2021, USPSTF 2021).  Additionally,  21% of persons with diabetes either were unaware of the diagnosis or did not report it as a known diagnosis in some studies (CDC 2020). 

Benefits: The reviewed randomized trials of screening vs. no screening (ADDITION trial and Ely Study) did not identify a mortality benefit with screening, but they were limited by a relatively short period (ten years) of follow up. For patients with newly diagnosed Type 2 diabetes, interventions have been shown to improve mortality at 20 years (UKPDS 1999). Similarly, lifestyle interventions have been shown to reduce progression to diabetes for patients with prediabetes (Balk et al, 2015, Gong et al, 2015) . It is important to remember the difficulty of implementing lifestyle interventions similar to those included in studies. 

Harms: There are minimal harms to screening for prediabetes and type II diabetes.

Screening Specifics 

Recommended screening options include:

1) Hemoglobin A1c 

2) Fasting glucose 

3) Glucose tolerance testing (high sensitivity, but difficult to obtain)

How often? An optimal screening interval has not been established based on evidence, but the USPSTF identifies 3 years as a reasonable time interval for repeat screening. 

Additional Screening Considerations 

For Asian American patients, consider screening at a lower BMI cutoff of  >23 as a BMI cutoff of 25 has been shown to underestimate risk (Araneta et al, 2015). Screening at earlier ages may be prudent in patients from groups with a disproportionately high prevalence of diabetes including American Indian/Alaska Native, Asian American, Native Hawaiian/Pacific Islander, Black, Hispanic/Latino persons (Lancet editorial 2018). Dr. Tseng reminds us that screening should also be considered in the setting of other risk factors for prediabetes/diabetes including hypertension or hyperlipidemia, but this was not in the scope of the current recommendation.

Other Recommendations

  • The American Diabetes Association recommends screening 1) all adults ages 45 years or older and 2) adults who have overweight or obesity with > 1 additional risk factors for diabetes regardless of age (ADA 2018).
  • The American Association of Clinical Endocrinology recommends screening 1) all adults ages 45 years or older 2) adults with risk factors at any age (AACE 2015). 


  1. USPSTF 2021 Prediabetes & Type 2 Diabetes Screening
  2. Rooney et al 2021 Risk of Progression to Diabetes Among Older Adults 
  3. A Pretty Good Joke Book by  ​​Garrison Keillor

*The Curbsiders participates in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising commissions by linking to Amazon. Simply put, if you click on our links and buy something we earn a (very) small commission, yet you don’t pay any extra.


Listeners will review the updated 2021 USPSTF Prediabetes and Type 2 Diabetes screening guidelines. 

Learning objectives

After listening to this episode listeners will…

  1. Review the updated USPSTF recommendation for prediabetes and type 2 diabetes screening in nonpregnant adults
  2. Identify recommended screening modalities for prediabetes and type 2 diabetes


Dr. Tseng reports no relevant financial disclosures. The Curbsiders report no relevant financial disclosures. 


Gibson EG, Williams, P, Tseng C,. “#309 USPSTF Update: Prediabetes & Type 2 DM Screening”. The Curbsiders Internal Medicine Podcast. December 6, 2021.


  1. December 7, 2021, 12:59pm Jonathan Meyer writes:

    Thanks for your review on Diabetes screening, it was a good review and discussion which I enjoyed as always. You mentioned CDL drivers, and they actually can drive with Insulin-Dependent Diabetes. They fill out a form with their treating physician to record that there are not complications like severe hypoglycemia, and are approved to drive.

    • September 30, 2022, 12:06pm Ask Curbsiders writes:

      Great info! Thanks for sharing!

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The Curbsiders are partnering with VCU Health Continuing Education to offer FREE continuing education credits for physicians and other healthcare professionals. Visit and search for this episode to claim credit.

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