Prediabetes and Diabetes Screening Eligibility and Detection in US Adults After Changes to US Preventive Services Task Force and American Diabetes Association Recommendations

Abstract

This cross-sectional study using NHANES data assesses the proportion of asymptomatic US adults eligible for screening based on new vs current US Preventive Services Task Force and American Diabetes Association screening guidelines, overall and among those with prediabetes or undiagnosed diabetes.

Prediabetes and type 2 diabetes have reached epidemic levels and are associated with major morbidity and mortality. The US Preventive Services Task Force (USPSTF) and the American Diabetes Association (ADA) recently recommended lowering the starting age for diabetes screening to 35 years to facilitate earlier detection and treatment.^1,2 We estimated the proportion of asymptomatic US adults eligible for screening based on new vs current USPSTF and ADA screening guidelines, overall and among those with prediabetes or undiagnosed diabetes.

Methods

We analyzed data from the 2015-2020 National Health and Nutrition Examination Survey (NHANES), a nationally representative, cross-sectional survey of the noninstitutionalized US population. NHANES consisted of in-person interviews and physical examinations that included laboratory testing.

We included adults (aged ≥20 years) without a history of diagnosed prediabetes or diabetes who were fasting, were not pregnant, and had hemoglobin A_1c (HbA_1c), fasting plasma glucose (FPG), weight, and height measured during the examination.

We defined prediabetes as an FPG level of 100 to 125 mg/dL or HbA_1c of 5.7% to 6.4% and undiagnosed diabetes as an FPG level of 126 mg/dL or greater or HbA_1c of 6.5% or greater. In sensitivity analyses, we considered a “confirmatory” definition of undiagnosed diabetes (FPG ≥126 mg/dL and HbA_1c ≥6.5%). We calculated body mass index (BMI) as weight in kilograms divided by height in meters squared using measured weight and height.

We selected screening guidelines based on the first year new recommendations were introduced. We defined screening eligibility as (1) aged 40 to 70 years with a BMI of 25 or greater (USPSTF, 2015); (2) aged 35 to 70 years with a BMI of 25 or greater (USPSTF, 2021); (3) aged 45 years or older or a BMI of 25 or greater and 1 or more risk factors (ADA, 2003); or (4) aged 35 years or older or a BMI of 25 or greater and 1 or more risk factors (ADA, 2022) (eAppendix in the Supplement).^1,2,3

We estimated the proportion of US adults eligible for screening based on the USPSTF 2015, USPSTF 2021, ADA 2003, and ADA 2022 guidelines, overall and among those with prediabetes or undiagnosed diabetes. All analyses were conducted using Stata version 17.0 (StataCorp) and used survey weights to generate estimates representative of the US adult population. NHANES study protocols were approved by the National Center for Health Statistics institutional review board, and all participants provided written informed consent.

Results

Among 4836 eligible adult participants, 4480 (92.6%) had HbA_1c, FPG, and BMI data available and were included in the study (mean age, 45.6 years; 51.2% women). The weighted proportion eligible for screening increased from 36.3% (95% CI, 34.1%-38.5%) to 43.0% (95% CI, 40.5%-45.6%) comparing USPSTF 2015 with USPSTF 2021 guidelines and from 76.7% (95% CI, 73.8%-79.3%) to 82.9% (95% CI, 80.1%-85.3%) comparing ADA 2003 with ADA 2022 guidelines (Table). Screening eligibility rose among those with prediabetes comparing USPSTF 2015 with USPSTF 2021 guidelines (from 50.1% to 56.2%) and ADA 2003 with ADA 2022 guidelines (from 89.4% to 93.7%). Among adults with undiagnosed diabetes, screening eligibility increased comparing USPSTF 2015 with USPSTF 2021 guidelines (from 58.7% to 67.8%) but not comparing ADA 2003 with ADA 2022 guidelines (from 97.6% to 99.1%). Results were similar using a confirmatory definition of diabetes.

Table. Proportion of US Adults Eligible for Prediabetes and Diabetes Screening According to USPSTF and ADA Guidelines, Overall and Among Those With Prediabetes or Undiagnosed Diabetes, NHANES 2015-2020^a.

	Unweighted No. eligible for screening	Weighted percentage eligible for screening (95% CI)
Overall (N = 4480)
USPSTF 2015 guidelines	1640	36.3 (34.1-38.5)
USPSTF 2021 guidelines	1939	43.0 (40.5-45.6)
ADA 2003 guidelines	3657	76.7 (73.8-79.3)
ADA 2022 guidelines	3898	82.9 (80.1-85.3)
Adults with prediabetes (n = 1961)b
USPSTF 2015 guidelines	933	50.1 (47.3-52.9)
USPSTF 2021 guidelines	1046	56.2 (53.3-59.0)
ADA 2003 guidelines	1823	89.4 (85.0-92.5)
ADA 2022 guidelines	1882	93.7 (90.3-96.0)
Adults with undiagnosed diabetes (n = 164)c
USPSTF 2015 guidelines	96	58.7 (44.5-71.5)
USPSTF 2021 guidelines	109	67.8 (53.1-79.7)
ADA 2003 guidelines	158	97.6 (93.0-99.2)
ADA 2022 guidelines	161	99.1 (95.9-99.8)
Adults with confirmed undiagnosed diabetes (n = 52)d
USPSTF 2015 guidelines	29	50.9 (32.8-68.7)
USPSTF 2021 guidelines	37	73.2 (53.9-86.5)
ADA 2003 guidelines	51	98.3 (88.1-99.8)
ADA 2022 guidelines	52	100

Abbreviations: ADA, American Diabetes Association; BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); HbA_1c, hemoglobin A_1c; NHANES, National Health and Nutrition Examination Survey; USPSTF, US Preventive Services Task Force.

^a Screening criteria were defined as age 40 to 70 years and BMI of 25 or greater for USPTF 2015 guidelines; age 35 to 70 years and BMI of 25 or greater for USPTF 2021 guidelines; age 45 years or older or BMI of 25 or greater and 1 additional risk factor for ADA 2003 guidelines; and age 35 years or older or BMI of 25 or greater and 1 additional risk factor for ADA 2022 guidelines.

^b Prediabetes was defined as HbA_1c of 5.7% to 6.4% or fasting plasma glucose level of 100 to 125 mg/dL.

^c Undiagnosed diabetes was defined as HbA_1c of 6.5% or greater or fasting plasma glucose level of 126 mg/dL or greater.

^d Confirmed undiagnosed diabetes was defined as HbA_1c of 6.5% or greater and fasting plasma glucose level of 126 mg/dL or greater.

Discussion

Implementing the USPSTF 2021 and ADA 2022 guidelines would increase screening eligibility among US adults by approximately 6 to 7 percentage points, resulting in an approximate 4- to 6-percentage-point increase in prediabetes detection and an approximate 2- to 9-percentage-point increase in undiagnosed diabetes detection.

Screening, prevention, and treatment of diabetes in younger patients remains suboptimal.^4,5,6 Starting diabetes screening at age 35 years may place even greater demands on clinicians to care for younger populations. Expanding health care access, developing targeted outreach for high-risk individuals, and scaling prevention programs will be critical.

While the USPSTF 2021 guideline defines eligibility based on age and BMI, the ADA 2022 guideline considers a broader set of risk factors. Consequently, the ADA 2022 guideline identifies a larger portion of persons with prediabetes or diabetes compared with the USPSTF 2021 guideline but requires screening approximately twice as many people. Screening more than 80% of asymptomatic adults (ADA, 2022) may be cost prohibitive. Harmonizing recommendations may reduce confusion for clinicians and facilitate implementation.

Study limitations included the limited sample size in subgroups and declining response rate in NHANES. The analysis did not consider screening frequency and assumed complete implementation of all screening guidelines.

Section Editors: Jody W. Zylke, MD, Deputy Editor; Kristin Walter, MD, Associate Editor.

Supplement.

eAppendix. Definitions of Eligibility for Prediabetes and Diabetes Screening According to the USPSTF 2015, USPSTF 2021, ADA 2003, and ADA 2022 Guidelines