Use Age, Not Weight, to Screen for Diabetes; Assess Over 35s

Marlene Busko

March 28, 2023

Universal screening of all US adults ages 35 to 70 years old for prediabetes and type 2 diabetes, regardless of body mass index (BMI), would provide the fairest means of detection, according to a new analysis.

This would better detect prediabetes and diabetes in ethnic groups that have a higher risk of diabetes at lower cutoffs. Compared with White individuals, Black or Hispanic adults have a higher risk of developing type 2 diabetes at a younger age, and Asian, Hispanic, and Black Americans all have a higher risk of developing it at a lower BMI.   

In the new study, researchers examined six different screening scenarios in a nationally representative sample without diabetes.

They compared screening for prediabetes and type 2 diabetes using criteria from the 2021 US Preventive Services Task Force (USPSTF) recommendations with the 2015 USPSTF recommendations, as well as four other screening thresholds with lower age or weight.

Universal screening for prediabetes and diabetes at age 35 to 70, regardless of BMI — which appears to be the sweet spot for most equitable detection in different races — may be easier to put into practice because it will mean clinicians don't have to remember alternate cutoffs for different patient groups, the researchers suggest.

"All major racial and ethnic minority groups develop diabetes at lower weights than White adults, and it's most pronounced for Asian Americans," lead author Matthew J. O'Brien, MD, explained in a press release.

"If we make decisions about diabetes testing based on weight we will miss some people from racial and ethnic minority groups who are developing prediabetes and diabetes at lower weights," said O'Brien, of Northwestern University Feinberg School of Medicine, Chicago, Illinois.

Going forward, to achieve equity in diagnosing prediabetes and diabetes "also requires addressing structural barriers [facing racial and ethnic minorities], which include not having a usual source of primary care, lacking health insurance, or having copays for screening tests based on insurance coverage," the authors note in their paper published online March 24 in the American Journal of Preventive Medicine.

There is also a need for further study to examine the cost-effectiveness of any approach, and to study the impact of screening criteria on diagnosis, treatment, and outcomes in diverse populations.

Nationally Representative Sample, Six Screening Scenarios

In the overall US population, 81% of adults with prediabetes are unaware they have it, say O'Brien and colleagues, and 23% of diabetes cases are undiagnosed.

And Black, Hispanic, or Asian individuals have a nearly twofold higher prevalence of diabetes than White individuals.

The 2021 USPSTF recommendations state that clinicians should screen asymptomatic adults age 35 to 70 years with overweight/obesity (BMI ≥ 25 kg/m2) and "should consider screening at an earlier age in persons from groups with disproportionately high incidence and prevalence (American Indian/Alaska Native, Asian American, Black, Hispanic/Latino, or Native Hawaiian/Pacific Islander persons) or in persons who have a family history of diabetes, a history of gestational diabetes, or a history of polycystic ovarian syndrome, and at a lower BMI in Asian American persons. Data suggest that a BMI of 23 or greater may be an appropriate cut point in Asian American persons."

O'Brien and colleagues identified 3243 nonpregnant adults without diagnosed diabetes who participated in the National Health and Nutrition Examination Survey (NHANES) in 2017-2020 and had an A1c blood test. (Half also had a fasting plasma glucose test.)

First, they compared screening using the more recent and earlier USPSTF criteria:

  • BMI ≥ 25 kg/m2 and age 35 to 70 (2021 criteria)

  • BMI ≥ 25 kg/m2 and age 40 to 70 (2015 criteria)

They estimate that 13.9 million more adults would be eligible for screening using the 2021 versus the 2015 screening criteria.

The increases in screening eligibility were highest in Hispanic individuals (30.6%), followed by Asian individuals (17.9%), Whites (14.0%), and Blacks (13.9%).

Using the USPSTF 2021 versus 2015 screening criteria resulted in marginally higher sensitivity (58.6% vs 52.9%) but lower specificity (69.3% vs 76.4%) overall, as well as within each racial group.

Next, the researchers examined screening at two lower age cutoffs and two lower BMI cutoffs:

  • BMI ≥ 25 kg/m2 and age 30 to 70

  • BMI ≥ 25 kg/m2 and age 18 to 70

  • Age 35 to 70 and BMI ≥ 23 kg/m2

  • Age 35 to 70 and any BMI

Screening at these lower age and weight thresholds resulted in even greater sensitivity and lower specificity than using the 2021 USPSTF criteria, especially among Hispanic, non-Hispanic Black, and Asian adults.

However, screening all adults age 35 to 70 years regardless of BMI yielded the most equitable detection of prediabetes and diabetes — with a sensitivity of 67.8% and a specificity of 52.1% in the overall population, and a sensitivity of 70.1%, 70.4%, 68.4%, and 67.6%, and a specificity of 53.8%, 59.9%, 56.2%, and 48.9%, in the Asian, Black, Hispanic, and White subgroups, respectively.

The American Diabetes Association currently recommends screening all adults age ≥ 35 years, or at any age if they have overweight/obesity and an additional diabetes risk factor, the researchers note.

The study was partly funded by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health. The authors have reported no relevant financial relationships.

Am J Prev Med. Published online March 24, 2023. Article

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