Dataset Information

Use of HbA1c for diagnoses of diabetes and prediabetes: comparison with diagnoses based on fasting and 2-hr glucose values and effects of gender, race, and age.

ABSTRACT:

Background

Glycated hemoglobin (HbA1c) has been advocated for the diagnosis of diabetes and prediabetes. Its performance has been commonly assessed in corroboration with elevated fasting plasma glucose (FPG), but not the combination of FPG and 2-hr glucose values. This study assesses receiver operating characteristics (ROC) curves of HbA1c pertaining to the diagnoses of prediabetes and diabetes by FPG and/or 2-hr glucose, and the effects of age, gender, and race.

Methods

We assessed the utility of HbA1c for diagnosing diabetes and prediabetes among 5395 adults without known diabetes from the National Health and Nutrition Examination Survey (NHANES) 2005-2010.

Results

Current cutoffs of HbA1c for diabetes (6.5%) or prediabetes (5.7%) exhibited low sensitivity (0.249 and 0.354, respectively) and high specificity in identifying patients diagnosed using both FPG and 2-hr glucose, resulting in large false-negative rates (75.1% and 64.9%). Misdiagnosis rates increased with age and in non-Hispanic whites and Mexican Americans. When HbA1c was combined with FPG for diagnoses, the false-negative rate remained high for diabetes (45.7%), but was reduced for prediabetes (9.2%).

Conclusions

When assessed against diagnoses using both FPG and 2-hr glucose, HbA1c had low sensitivity and high specificity for identifying diabetes and prediabetes, which varied as a function of age and race. Regarding recently released American Diabetes Association (ADA) and joint European guidelines, it is important to consider that HbA1c values below 6.5% and 5.7% do not reliably exclude the presence of diabetes and prediabetes, respectively. Overall, the data argue for greater use of oral glucose tolerance tests (OGTTs) and both FPG and 2-hr glucose values for diagnosis of diabetes and prediabetes.

SUBMITTER: Guo F

PROVIDER: S-EPMC4088353 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature

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Publications

Use of HbA1c for diagnoses of diabetes and prediabetes: comparison with diagnoses based on fasting and 2-hr glucose values and effects of gender, race, and age.

Guo Fangjian F Moellering Douglas R DR Garvey W Timothy WT

Metabolic syndrome and related disorders 20140210 5

<h4>Background</h4>Glycated hemoglobin (HbA1c) has been advocated for the diagnosis of diabetes and prediabetes. Its performance has been commonly assessed in corroboration with elevated fasting plasma glucose (FPG), but not the combination of FPG and 2-hr glucose values. This study assesses receiver operating characteristics (ROC) curves of HbA1c pertaining to the diagnoses of prediabetes and diabetes by FPG and/or 2-hr glucose, and the effects of age, gender, and race.<h4>Methods</h4>We assess ...[more]

PMID: 24512556

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Project description:BackgroundBoth fasting plasma glucose (FPG) and HbA1c are recommended for the diagnosis of diabetes and prediabetes by the American Diabetes Association (ADA), and for diabetes by the World Health Organization. The ADA guidance is influential on clinical practice in many developing countries, including in the Caribbean and Latin America. We aimed to compare the prevalence and characteristics of individuals identified as having diabetes and prediabetes by FPG and HbA1c in a predominantly African ancestry Caribbean population.MethodsA representative population-based sample of 1234 adults (≥25 years of age) resident in Barbados was recruited. Standard methods with appropriate quality control were used to collect data on height, weight, blood pressure, fasting lipids and history of diagnosed diabetes, and to measure fasting glucose and HbA1c. Those with previously diagnosed diabetes (n = 192) were excluded from the analyses. Diabetes was defined as: FPG ≥7.0 mmol/L or HbA1c ≥6.5%; prediabetes as: FPG ≥5.6 to <7mmol/L or HbA1c ≥5.7 to <6.5%.ResultsComplete data were available on 939 participants without previously diagnosed diabetes. The prevalence of undiagnosed diabetes was higher, but not significantly so, by HbA1c (4.9%, 95% CI 3.5, 6.8) vs FPG (3.5%, 2.4, 5.1). Overall 79 individuals had diabetes by either measure, but only 21 on both. The prevalence of prediabetes was higher by HbA1c compared to FPG: 41.7% (37.9, 45.6) vs 15.0% (12.8, 17.5). Overall 558 individuals had prediabetes by either measure, but only 107 on both. HbA1c, but not FPG, was significantly higher in women than men; and FPG, but not HbA1c, was significantly associated with raised triglycerides and low HDL cholesterol.ConclusionThe agreement between FPG and HbA1c defined hyperglycaemia is poor. In addition, there are some differences in the phenotype of those identified, and HbA1c gives a much higher prevalence of prediabetes. The routine use of HbA1c for screening and diagnosis in this population would have major implications for clinical and public health policies and resources. Given the lack of robust evidence, particularly for prediabetes, on whether intervention in the individuals identified would improve outcomes, this approach to screening and diagnosis cannot be currently recommended for this population.

Project description:AimsTo evaluate the efficacy and safety of dulaglutide 1.5 and 0.75?mg in patients with type 2 diabetes by subgroups of gender, duration of diabetes and baseline glycated haemoglobin (HbA1c) in the dulaglutide clinical development programme (AWARD-1 to -6 and -8 clinical trials).MethodsChange in HbA1c was analysed by gender, duration of diabetes (<5, ?5?years and <10, ?10?years), and baseline HbA1c (<8.5%, ?8.5%) in pooled and individual studies. Changes from baseline in weight, hypoglycaemia and gastrointestinal adverse events were evaluated for individual trials.ResultsIn the pooled analysis of patients treated with dulaglutide 1.5?mg at 6?months, the reductions in HbA1c from baseline were similar across gender (men: least squares [LS] mean -1.26% [95% confidence interval {CI} -1.36, -1.16]; women: LS mean -1.33% [95% CI -1.43, -1.24]) and among duration of diabetes subgroups (<5?years: LS mean -1.32% [95% CI -1.43, -1.22]; ?5 and <10?years: LS mean -1.33% [95% CI -1.43, -1.22]; ?10?years: -1.24% [95% CI -1.35, -1.14]). Patients with baseline HbA1c ?8.5% had greater HbA1c reductions than patients with baseline HbA1c <8.5%, (?8.5%: LS mean -1.86% [95% CI -1.97, -1.75]; <8.5%: LS mean -1.02% [95% CI -1.12, -0.93]). Reductions in fasting blood glucose (FBG) were consistent with HbA1c changes. Similar results were observed with dulaglutide 0.75?mg. In general, body weight changes were similar among duration of diabetes and in baseline HbA1c subgroups, respectively; women had a numerically greater weight loss or less weight gain than men with both dulaglutide doses. There was no clinically meaningful difference in hypoglycaemia trends by gender or duration of diabetes. Hypoglycaemia incidence and rate were generally lower in patients with baseline HbA1c ?8.5% than in those with <8.5%, except for the AWARD-4 study (combination with mealtime insulin).ConclusionsAcross the AWARD studies, dulaglutide demonstrated significant improvements in glycaemic control irrespective of gender, duration of diabetes, or baseline HbA1c, with greater HbA1c and FBG reductions in patients with a higher baseline HbA1c. Dulaglutide was well tolerated, with a safety profile similar to other glucagon-like peptide-1 receptor agonists.

Project description:Prediabetes is common and associated with poor prognosis in patients with acute coronary syndrome and those undergoing revascularization. However, the impact of prediabetes on prognosis in patients with coronary intermediate lesions remains unclear. The objective of the current study is to explore the impact of prediabetes and compare the prognostic value of the different definitions of prediabetes in patients with coronary intermediate lesions. A total of 1532 patients attending Fuwai hospital (Beijing, China), with intermediate angiographic coronary lesions, not undergoing revascularization, were followed-up from 2013 to 2021. Patients were classified as normal glucose tolerance (NGT), prediabetes and diabetes according to various definitions based on HbA1c or admission fasting plasma glucose (FPG). The primary endpoint was defined as major adverse cardiovascular events (MACE), the composite endpoint of all-cause death, non-fatal myocardial infarction and repeated revascularization therapy. Multivariate cox regression model was used to explore the association between categories of abnormal glucose category and MACE risk. The proportion of patients defined as prediabetes ranged from 3.92% to 47.06% depending on the definition used. A total of 197 MACE occurred during a median follow-up time of 6.1 years. Multivariate cox analysis showed that prediabetes according to the International Expert Committee (IEC) guideline (6.0 ≤ HbA1c < 6.5%) was associated with increased risk of MACE compared with NGT (hazard ratio [HR]: 1.705, 95% confidence interval [CI] 1.143-2.543) and after confounding adjustment (HR: 1.513, 95%CI 1.005-2.277). Consistently, the best cut-off point of glycated haemoglobin (HbA1c) identified based on the Youden's index was also 6%. Restricted cubic spline analysis delineated a linear positive relationship between baseline HbA1c and MACE risk. Globally, FPG or FPG-based definition of prediabetes was not associated with patients' outcome. In this cohort of patients with intermediate coronary lesions not undergoing revascularization therapy, prediabetes based on the IEC-HbA1c definition was associated with increased MACE risk compared with NGT, and may assist in identifying high-risk patients who can benefit from early lifestyle intervention.

Dataset Information

Use of HbA1c for diagnoses of diabetes and prediabetes: comparison with diagnoses based on fasting and 2-hr glucose values and effects of gender, race, and age.

Background

Methods

Results

Conclusions

Publications

Use of HbA1c for diagnoses of diabetes and prediabetes: comparison with diagnoses based on fasting and 2-hr glucose values and effects of gender, race, and age.

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