Screening all adults, aged 35-70 years, for diabetes and prediabetes regardless of the BMI would diagnose more cases of diabetes and prediabetes, especially among the at-risk ethnic populations, who are likely to develop diabetes at a lower body weight, suggests a new study published March 24, 2023 in the American Journal of Preventive Medicine.^1,2

In this study, the investigators compared the screening criteria for prediabetes and type 2 diabetes as defined by the USPSTF in its most recent recommendations issued in 2021 (BMI ≥ 25 kg/m2 and age 35 to 70 years) with those from 2015 (BMI ≥ 25 kg/m2 and age 40 to 70 years). They also evaluated four other screening cut-offs of age and BMI: 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 and age 35 to 70 and any BMI.2

For this they recruited 3243 nonpregnant adults from the 2017-2020 National Health and Nutrition Examination Survey (NHANES). None of the participants had been earlier diagnosed with diabetes. A fasting plasma glucose of 100 mg/dL or more or hemoglobin A1c of 5.7% or greater were defined as prediabetes and undiagnosed diabetes.

Overall, the 2021 USPSTF criteria were slightly more sensitive than the 2015 criteria (61.6 vs 52.9%, respectively), but they had lower specificity (72.2 vs 76.4%, respectively) and also within each racial and ethnic group. Compared to the 2021 USPSTF criteria, the lower age and BMI cutoffs had greater sensitivity and lower specificity, especially among the Asian, Hispanic, non-Hispanic Black adults. However, screening all the participants in the age group of 35-70 years with any BMI provided the highest results in terms of detection of prediabetes and diabetes with an overall sensitivity of 67.8% and a specificity of 52.1%; this was consistent across all the racial and ethnic groups examined.

In its latest 2021 recommendation statement, the USPSTF lowered the age of screening from 40 to 35 years in the 2015 guidelines. All adults, aged 35 to 70 years who are overweight and have obesity and no symptoms of diabetes should be screened for prediabetes and type 2 diabetes using fasting plasma glucose or HbA1c level or an oral glucose tolerance test. In at-risk individuals, screening should be done at an earlier age if the patient is an American Indian/Alaska Native, Native Hawaiian/Pacific Islander, Black, Hispanic/Latino. In Asian Americans, a BMI cutoff of ≥23 should be considered for screening.³ The screening should be repeated every 3 years if the blood glucose levels are normal.

In the 2023 Standards of Care in Diabetes, the American Diabetes Association (ADA) recommends screening all asymptomatic adults aged 35 years and older with overweight/obesity and the presence of one or more risk factors such as positive family history of diabetes, heart disease, hypertension, dyslipidemia, prediabetes, polycystic ovarian syndrome (PCOS), history of gestational diabetes (GDM).⁴ The ADA also recommends screening every 3 years in case of normal glucose levels. However, it adds a caveat that symptomatic persons or those who acquire risk factors should be screened earlier.

The BMI cutoffs for screening differ among various racial ethnic groups. For instance, in Asian Americans, a BMI cutoff of ≥23 should be considered for screening as recommended by the USPSTF and ADA. Routine screening of all adults between the ages of 35 and 70 years, irrespective of their BMI, would yield a better success rate in the diagnosis of diabetes and prediabetes, that would have been otherwise missed if the BMI cutoffs for screening had been applied, as is evident from this study.

References

1. Matthew J. OBrien, et al. Screening for prediabetes and diabetes: clinical performance and implications for health equity. Am J Prev Med. Published online March 24, 2023. DOI: https://doi.org/10.1016/j.amepre.2023.01.007.
2. Use age, not weight, to screen for diabetes; assess over 35s - Medscape - Mar 28, 2023.
3. Prediabetes and Type 2 Diabetes: Screening. August 24, 2021. Available at: https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/screening-for-prediabetes-and-type-2-diabetes. Accessed on April 3, 2023.
4. 2. ElSayed NA, et al, on behalf of the American Diabetes Association. Classification and Diagnosis of Diabetes: Standards of Care in Diabetes-2023. Diabetes Care. 2023 Jan 1;46(Suppl 1):S19-S40. doi: 10.2337/dc23-S002.