OBJECTIVE Screening for diabetes is typically done using hemoglobin A_1c (HbA_1c) or fasting plasma glucose (FPG). The 2019 Endocrine Society guidelines recommend further testing using an oral glucose tolerance test (OGTT) in older adults with prediabetic HbA_1c or FPG. We evaluated the impact of this recommendation on diabetes prevalence, eligibility for glucose-lowering treatment, and estimated cost of implementation in a nationally representative sample.

RESEARCH DESIGN AND METHODS We included 2,236 adults aged ≥65 years without known diabetes from the 2005–2016 National Health and Nutrition Examination Survey. Diabetes was defined using: 1) the Endocrine Society approach (HbA_1c ≥6.5%, FPG ≥126 mg/dL, or 2-h plasma glucose ≥200 mg/dL among those with HbA_1c 5.7–6.4% or FPG 100–125 mg/dL); and 2) a standard approach (HbA_1c ≥6.5% or FPG ≥126 mg/dL). Treatment eligibility was defined using HbA_1c cut points (≥7 to ≥9%). OGTT screening costs were estimated using Medicare fee schedules.

RESULTS Diabetes prevalence was 15.7% (∼5.0 million) using the Endocrine Society’s approach and 7.3% (∼2.3 million) using the standard approach. Treatment eligibility ranged from 5.4 to 0.06% and 11.8–1.3% for diabetes cases identified through the Endocrine Society or standard approach, respectively. By definition, diabetes identified exclusively through the Endocrine Society approach had HbA1_1c <6.5% and would not be recommended for glucose-lowering treatment. Screening all older adults with prediabetic HbA_1c/FPG (∼18.3 million) with OGTT could cost between $737 million and $1.7 billion.

CONCLUSIONS Adopting the 2019 Endocrine Society guidelines would substantially increase the number of older adults classified as having diabetes, require significant financial resources, but likely offer limited benefits.