Changes in Screening Practices for Prediabetes and Diabetes Since the Recommendation for Hemoglobin A(1c) Testing.

Screening involves the presumptive identification of asymptomatic individuals at increased risk for unrecognized disease. We examined changes in screening practices for prediabetes and diabetes since January 2010, when HbA1c was first recommended as an option for screening and diagnosis. We studied members without diabetes of an HMO ≥45 years of age continuously enrolled for ≥3 years and assigned to primary care clinicians affiliated with a large academic health system. We defined screening as the first oral glucose tolerance test, HbA1c, or glucose test performed between 2010 and 2014. Of 12,772 eligible patients, 9,941 (78%) were screened at least once over 3 years. HbA1c was the initial screening test 14% of the time and glucose 86% of the time. Of those screened with HbA1c, 63% had abnormal results defined as HbA1c ≥5.7% (≥39 mmol/mol). Of those tested with glucose, 30% had abnormal results defined as glucose ≥100 mg/dL, and 5% had abnormal results defined as glucose ≥126 mg/dL. Patients with abnormal HbA1c levels and those with glucose levels ≥126 mg/dL were equally likely to be scheduled for follow-up appointments (41% vs. 39%), but those with abnormal HbA1c levels were more likely to be diagnosed with prediabetes or diabetes (36% vs. 26%). As we observed in 2004, rates of screening are high. HbA1c is still used less frequently than glucose for screening but is more likely to result in a clinical diagnosis. Evidence to support guidelines to define the role of random glucose screening, including definition of appropriate cut points and follow-up, is needed.

Evron JM ，Herman WH ，McEwen LN 《-》

Clinical and Public Health Implications of 2019 Endocrine Society Guidelines for Diagnosis of Diabetes in Older Adults.

Screening for diabetes is typically done using hemoglobin A1c (HbA1c) 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 HbA1c 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. 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 (HbA1c ≥6.5%, FPG ≥126 mg/dL, or 2-h plasma glucose ≥200 mg/dL among those with HbA1c 5.7-6.4% or FPG 100-125 mg/dL); and 2) a standard approach (HbA1c ≥6.5% or FPG ≥126 mg/dL). Treatment eligibility was defined using HbA1c cut points (≥7% to ≥9%). OGTT screening costs were estimated using Medicare fee schedules. 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% to 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 HbA11c <6.5% and would not be recommended for glucose-lowering treatment. Screening all older adults with prediabetic HbA1c/FPG (∼18.3 million) with OGTT could cost between $737 million and $1.7 billion. 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.

Fang M ，Echouffo-Tcheugui JB ，Selvin E 《-》

Erythrocytosis and Performance of HbA1c in Detecting Diabetes on an Oxygen-Deficient Plateau: A Population-based Study.

The hemoglobin A1c (HbA1c) test is a standard test for diabetes screening and diagnosis. To evaluate A1c performance for diabetes screening in high-altitude polycythemia compared to a population with a high proportion of people living in an oxygen-deficient environment. A population-based epidemiological survey was conducted. The cities Lhasa and Shigatse were selected. Volunteers were recruited through educational advertisements about diabetes. A total of 1401 Tibetan adults without known diabetes. Oral glucose tolerance test (OGTT), HbA1c, and complete blood cell count were performed. Hemoglobin A1c was evaluated using high-performance liquid chromatography, and serum glucose level, using the hexokinase method. World Health Organization criteria were used to define diabetes and prediabetes. Hemoglobin A1c test performance was evaluated using receiver operating characteristic analysis. The participants' mean age was 44.3 ± 15.0 years; 33.3% of the participants were men and 38.6% lived in urban areas. The prediabetes and diabetes prevalence rates were 7.5% and 3.6%, respectively. The optimal HbA1c cutoff for detecting diabetes was 46 mmol/mol (6.4%), with a sensitivity and specificity of 60.8% and 93.6%, respectively. The cutoff for detecting diabetes was 6.7% (50 mmol/mol) in subjects with high-altitude polycythemia (HAPC). The relationship between red blood cell (RBC) counts and HbA1c was significant (P < 0.001), while there was no correlation between hemoglobin (Hb) and HbA1c (P = 0.085). Multiple linear regression analysis showed that after adjusting for age and fasting serum glucose or 2-hour OGTT (OGTT2h) serum glucose, RBC count and not Hb level was an independent risk factor for HbA1c (β = 0.140, P < 0.001). The optimal HbA1c cutoff for detecting diabetes was 46 mmol/mol (6.4%) in Tibet. Red blood cell count was an independent risk factor for elevated HbA1c, and HAPC may affect the predictive ability of HbA1c.

Ren Q ，Lv X ，Yang L ，Yue J ，Luo Y ，Zhou L ，Meng S ，Yang S ，Puchi B ，Zhou X ，Ji L ... -  《-》

Prevalence and phenotype of diabetes and prediabetes using fasting glucose vs HbA1c in a Caribbean population.

Unwin N ，Howitt C ，Rose AM ，Samuels TA ，Hennis AJ ，Hambleton IR ... -  《-》

Performance of HbA1c versus oral glucose tolerance test (OGTT) as a screening tool to diagnose dysglycemic status in high-risk Thai patients.

Thewjitcharoen Y ，Jones Elizabeth A ，Butadej S ，Nakasatien S ，Chotwanvirat P ，Wanothayaroj E ，Krittiyawong S ，Himathongkam T ，Himathongkam T ... -  《BMC Endocrine Disorders》