The 1-hour post-load glucose level is more effective than HbA1c for screening dysglycemia
- 668 Downloads
To assess the performance of HbA1c and the 1-h plasma glucose (PG ≥ 155 mg/dl; 8.6 mmol/l) in identifying dysglycemia based on the oral glucose tolerance test (OGTT) from a real-world clinical care setting.
This was a diagnostic test accuracy study. For this analysis, we tested the HbA1c diagnostic criteria advocated by the American Diabetes Association (ADA 5.7–6.4 %) and International Expert Committee (IEC 6.0–6.4 %) against conventional OGTT criteria. We also tested the utility of 1-h PG ≥ mg/dl; 8.6 mmol/l. Prediabetes was defined according to ADA-OGTT guidelines. Spearman correlation tests were used to determine the relationships between HbA1c, 1-h PG with fasting, 2-h PG and indices of insulin sensitivity and β-cell function. The levels of agreement between diagnostic methods were ascertained using Cohen’s kappa coefficient (Κ). Receiver operating characteristic (ROC) curve was used to analyze the performance of the HbA1c and 1-h PG test in identifying prediabetes considering OGTT as reference diagnostic criteria. The diagnostic properties of different HbA1c thresholds were contrasted by determining sensitivity, specificity and likelihood ratios (LR).
Of the 212 high-risk individuals, 70 (33 %) were identified with prediabetes, and 1-h PG showed a stronger association with 2-h PG, insulin sensitivity index, and β-cell function than HbA1c (P < 0.05). Furthermore, the level of agreement between 1-h PG ≥ 155 mg/dl (8.6 mmol/l) and the OGTT (Κ[95 % CI]: 0.40[0.28–0.53]) diagnostic test was stronger than that of ADA-HbA1c criteria 0.1[0.03–0.16] and IEC criteria (0.17[0.04–0.30]). The ROC (AUC[95 % CI]) for HbA1c and 1-h PG were 0.65[0.57–0.73] and 0.79[0.72–0.85], respectively. Importantly, 1-h PG ≥ 155 mg/dl (8.6 mmol/l) showed good sensitivity (74.3 % [62.4–84.0]) and specificity 69.7 % [61.5–77.1]) with a LR of 2.45. The ability of 1-h PG to discriminate prediabetes was better than that of HbA1c (∆AUC: −0.14; Z value: 2.5683; P = 0.01022).
In a real-world clinical practice setting, the 1-h PG ≥ 155 mg/dl (8.6 mmol/l) is superior for detecting high-risk individuals compared with HbA1c. Furthermore, HbA1c is a less precise correlate of insulin sensitivity and β-cell function than the 1-h PG and correlates poorly with the 2-h PG during the OGTT.
KeywordsHbA1c OGTT Dysglycemia Prediabetes 1-hour post-load glucose Diabetes prevention
This study was funded by CTSI Grant Number 1UL1RR029893 (NCRR, NIH, and the Schuman Foundation) and partly by NIH-K24-NR012226.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
This study was approved by the New York University School of Medicine Institutional Review Board.
Human and animal rights disclosure
All human rights were observed in keeping with Declaration of Helsinki 2008 (ICH GCP). There are no animal rights issues as this is a clinical study.
Informed consent was obtained from all individual participants included in the study.
- 2.Centers for Disease Control and Prevention (CDC) Awareness of prediabetes–United States, 2005–2010 (2013). MMWR Morbidity and mortality weekly report 62 (11):209–212Google Scholar
- 4.Herman WH, Ye W, Griffin SJ et al (2015) Early detection and treatment of type 2 diabetes reduce cardiovascular morbidity and mortality: a simulation of the results of the Anglo-Danish-Dutch study of intensive treatment in people with screen-detected diabetes in primary care (ADDITION-Europe). Diabetes Care: dc142459Google Scholar
- 15.Cosson E, Chiheb S, Cussac-Pillegand C et al (2013) Haemoglobin glycation may partly explain the discordance between HbA1c measurement and oral glucose tolerance test to diagnose dysglycaemia in overweight/obese subjects. Diabetes Metab 39(2):118–125. doi: 10.1016/j.diabet.2012.08.013 CrossRefPubMedGoogle Scholar
- 22.Sesti G, Hribal ML, Fiorentino TV, Sciacqua A, Perticone F (2014) Elevated 1 h postload plasma glucose levels identify adults with normal glucose tolerance but increased risk of non-alcoholic fatty liver disease. BMJ Open Diabetes Res Care 2(1):e000016. doi: 10.1136/bmjdrc-2014-000016 CrossRefPubMedPubMedCentralGoogle Scholar
- 27.Bianchi C, Miccoli R, Trombetta M et al (2013) Elevated 1-hour postload plasma glucose levels identify subjects with normal glucose tolerance but impaired beta-cell function, insulin resistance, and worse cardiovascular risk profile: the GENFIEV study. Journal Clin Endocrinol Metab 98(5):2100–2105. doi: 10.1210/jc.2012-3971 CrossRefGoogle Scholar
- 40.Manco M, Panunzi S, Macfarlane DP et al (2010) Relationship between Insulin S, Cardiovascular Risk C, One-hour plasma glucose identifies insulin resistance and beta-cell dysfunction in individuals with normal glucose tolerance: cross-sectional data from the Relationship between Insulin Sensitivity and Cardiovascular Risk (RISC) study. Diabetes Care 33(9):2090–2097. doi: 10.2337/dc09-2261 CrossRefPubMedPubMedCentralGoogle Scholar