One-hour post-load glucose improves the prediction of cardiovascular events in the OPERA study

Performance of the 1 h oral glucose tolerance test in predicting type 2 diabetes and association with impaired β-cell function in Asians: a national prospective cohort study

Background

Postprandial glucose concentration 1-h (1 h-PG) after an oral glucose tolerance test (OGTT) has similar or superior performance to 2 h-PG in predicting type-2 diabetes mellitus (T2DM) in several populations, and is simpler to obtain in clinical practice. However, studies in Asians are scarce. We investigated the utility of elevated baseline 1 h-PG in predicting T2DM incidence within three years, and its relationship with β-cell function in 1250 non-diabetic Asian participants.

Methods

Participants underwent an OGTT, an intravenous glucose challenge and a hyperinsulinemic-euglycemic clamp to determine glucose tolerance, acute insulin response (AIR) and insulin sensitivity at baseline. OGTTs were repeated every six months until study completion to monitor T2DM conversion.

Findings

The area under the receiver operating characteristic curve of 1 h-PG was not significantly different from 2 h-PG (AUC1h-PG = 0.883 vs. AUC2h-PG = 0.907; ΔAUC = -0.024, P = 0.124) and the optimal 1 h-PG cut-off was ≥10.7 mmol/L. When groups of high/low 1 h-PG and 2 h-PG at baseline were compared, AIR and disposition index were significantly lower in groups with high 1 h-PG, and both had a stronger correlation with 1 h-PG, indicating that impaired β-cell function was more strongly associated with elevated 1 h-PG than 2 h-PG.

Interpretation

The ability of 1 h-PG to detect Asians at risk of developing T2DM within three years is on par with 2 h-PG and the optimal cut-off is 10.7 mmol/L. Elevated 1 h-PG is associated with β-cell dysfunction. We conclude that 1 h-PG can be considered as a primary OGTT time point to identify Asians at risk for T2DM, allowing for screening at a reduced time and cost, and with lower patient burden.

Funding

National Medical Research Council (NMRC), Ministry of Health (MOH; Singapore) Industry Alignment Fund [NMRC/MOHIAFCat1/0048/2016] and Janssen Pharmaceuticals Inc. (USA).

Differences in target organ damage in individuals with intermediate hyperglycemia and type 2 diabetes identified by 1-hour plasma glucose during an oral glucose tolerance test

AIMS

The International Diabetes Federation (IDF) has recently recommended determination of 1-hour glucose during an oral glucose tolerance test (OGTT) to diagnose intermediate hyperglycemia (IH) and type 2 diabetes (T2D). Herein, we investigated the implications of IDF recommendation for characterizing the risk of cardiovascular target organ damage including left ventricular mass normalized by body surface area (LVM index [LVMI]), and myocardial mechano-energetic efficiency normalized by LVM (MEEi) in individuals with IH and T2D.

METHODS

LVMI, and MEEi were assessed in 1847 adults classified on the basis of fasting, 1-hour and 2- hour glucose during an OGTT according to the IDF recommendation as having normal glucose tolerance (NGT, n = 736), isolated impaired fasting glucose (iIFG, n = 105), IH (n = 676), and newly diagnosed T2D (n = 330).

RESULTS

As compared with NGT group, individuals with either IH or T2D exhibited significantly higher LVMI (97 ± 26, 109 ± 30, and 116 ± g/m2, P < 0.001, respectively), and a decrease in MEEi (0.42 ± 0.11, 0.37 ± 0.10, and 0.35 ± 0.11 ml/sec*g-1, P < 0.001, respectively). LVMI, and MEEi did not differ between NGT and iIFG groups.

CONCLUSION

The thresholds of 1-hour post-load glucose proposed by IDF as diagnostic criteria for IH and T2D are capable of detecting individuals at risk of cardiovascular target organ damage.

One-hour post-load plasma glucose level predicts future type 2 diabetes in a community-based study of Hong Kong Chinese workforce

BACKGROUND

We compared performance of high 1-hour PG level, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) in predicting type 2 diabetes in a longitudinal community-based cohort of Hong Kong Chinese.

METHODS

Between 2001 and 2003, 472 adults aged 18-55 years without diabetes underwent 75-gram oral glucose tolerance test (OGTT). Between 2012 and 2014, progression to diabetes was ascertained by reviewing medical records or repeating OGTT and HbA1c. We defined high 1-hour PG as PG ≥ 8.6 mmol/L at 1-hour.

RESULTS

In this cohort, 23.5% had normal glucose tolerance and high 1-hour PG, 10.0% had isolated IGT, 4.2% had isolated IFG. Over 12-year follow-up, 9.3% developed type 2 diabetes. In logistic regression, high 1-hour PG was associated with progression to type 2 diabetes with adjusted odds ratio (95% CI) of 4.20 (1.60, 12.40), independent of IFG, IGT and other clinical variables. Areas under ROC (95% CI) for type 2 diabetes were similar between 1-hour (0.84 [0.78, 0.89], 2-hour (0.79 [0.72, 0.86]) and fasting PG (0.79 [0.71, 0.86]).

CONCLUSION

High 1-hour PG identified young Chinese with 5-fold increased risk of type 2 diabetes independent of other intermediate hyperglycaemia status and clinical factors. 1-hour PG is similar to fasting and 2-hour PG in predicting type 2 diabetes.

International Diabetes Federation Position Statement on the 1-hour post-load plasma glucose for the diagnosis of intermediate hyperglycaemia and type 2 diabetes

Many individuals with intermediate hyperglycaemia (IH), including impaired fasting glycaemia (IFG) and impaired glucose tolerance (IGT), as presently defined, will progress to type 2 diabetes (T2D). There is confirmatory evidence that T2D can be prevented by lifestyle modification and/or medications, in people with IGT diagnosed by 2-h plasma glucose (PG) during a 75-gram oral glucose tolerance test (OGTT). Over the last 40 years, a wealth of epidemiological data has confirmed the superior value of 1-h plasma glucose (PG) over fasting PG (FPG), glycated haemoglobin (HbA1c) and 2-h PG in populations of different ethnicity, sex and age in predicting diabetes and associated complications including death. Given the relentlessly rising prevalence of diabetes, a more sensitive, practical method is needed to detect people with IH and T2D for early prevention or treatment in the often lengthy trajectory to T2D and its complications. The International Diabetes Federation (IDF) Position Statement reviews findings that the 1-h post-load PG ≥ 155 mg/dL (8.6 mmol/L) in people with normal glucose tolerance (NGT) during an OGTT is highly predictive for detecting progression to T2D, micro- and macrovascular complications, obstructive sleep apnoea, cystic fibrosis-related diabetes mellitus, metabolic dysfunction-associated steatotic liver disease, and mortality in individuals with risk factors. The 1-h PG of 209 mg/dL (11.6 mmol/L) is also diagnostic of T2D. Importantly, the 1-h PG cut points for diagnosing IH and T2D can be detected earlier than the recommended 2-h PG thresholds. Taken together, the 1-h PG provides an opportunity to avoid misclassification of glycaemic status if FPG or HbA1c alone are used. The 1-h PG also allows early detection of high-risk people for intervention to prevent progression to T2D which will benefit the sizeable and growing population of individuals at increased risk of T2D. Using a 1-h OGTT, subsequent to screening with a non-laboratory diabetes risk tool, and intervening early will favourably impact the global diabetes epidemic. Health services should consider developing a policy for screening for IH based on local human and technical resources. People with a 1-h PG ≥ 155 mg/dL (8.6 mmol/L) are considered to have IH and should be prescribed lifestyle intervention and referred to a diabetes prevention program. People with a 1-h PG ≥ 209 mg/dL (11.6 mmol/L) are considered to have T2D and should have a repeat test to confirm the diagnosis of T2D and then referred for further evaluation and treatment. The substantive data presented in the Position Statement provides strong evidence for redefining current diagnostic criteria for IH and T2D by adding the 1-h PG.

The Triglycerides and Glucose (TyG) Index Is Associated with 1-Hour Glucose Levels during an OGTT

BACKGROUND AND OBJECTIVES

Among individuals with normal glucose tolerance (NGT), subjects with high levels of plasma glucose (≥155 mg/dL) at sixty minutes during an oral glucose tolerance test (1h-OGTT) are at an increased risk of developing type 2 diabetes. We investigated the association between the triglycerides and glucose (TyG) index, a novel marker of insulin resistance, with 1h-OGTT glucose plasma concentrations.

MATERIAL AND METHODS

1474 non-diabetic Caucasian subjects underwent a 75 g OGTT and were divided into two groups according to the cutoff 1h-OGTT plasma glucose < 155 mg/dL (NGT-1h-low) and ≥ 155 mg/dL (NGT-1h-high). The TyG index was calculated as ln [fasting triglycerides (milligrams per deciliter) × fasting blood glucose (milligrams per deciliter)/2]. Multivariable linear and logistic regression analyses were used to establish the contribution of the TyG index to the variability of 1h-OGTT glucose, and how the former affected the risk of being NGT-1h-high.

RESULTS

1004 individuals were NGT-1h-low and 470 were NGT-1h-high. The TyG index was higher for NGT-1h-high (p = 0.001) individuals, and it was an independent factor influencing 1h-OGTT glycemia (β = 0.191, p < 0.001) after correcting for age, sex, and BMI. The TyG index was the strongest marker associated with the risk of being NGT-1h-high (OR = 1.703, CI 95% 1.34-2.17, p < 0.001) when compared with FPG (OR = 1.054, CI 95% 1.04-1.07, p < 0.001) and the HOMA-IR (OR = 1.156, CI 95% 1.08-1.23, p < 0.001).

CONCLUSIONS

Our study demonstrated that the TyG index, an efficient and cost-effective marker of insulin resistance, is associated with the variability of early post-challenge glucose levels and is an independent marker of being NGT-1h-high.

Elevated One-Hour Post-Load Glucose Is Independently Associated with Albuminuria: A Cross-Sectional Population Study

The purpose of this study was to examine and compare the associations between albuminuria and fasting (FPG), 1 h post-load (1 h PG) and 2 h post-load plasma glucose (2 h PG) in an oral glucose tolerance test (OGTT). A total of 496 people free of known diabetes (mean age 72 years) participated in the examinations including the OGTT with plasma glucose measurements at 0, 1, and 2 h and levels of HbA1c. Albuminuria was determined by the urinary albumin-to-creatinine ratio and was defined as ≥3.0 mg/mmol. Compared with those without albuminuria, participants with albuminuria had significantly higher 1 h PG and 2 h PG levels, but not FPG or HbA1c levels. An elevated 1 h PG increased the estimated odds ratio of albuminuria more than three times in people with prediabetic 1 h PG (8.6–11.5 mmol/L: OR 3.60; 95% CI 1.70–7.64) and diabetic 1 h PG (≥11.6 mmol/L: OR 3.05; 95% CI 1.29–7.23). After adjusting for blood pressure and age, the association of elevated 1 h PG with albuminuria remained significant. Prediabetic or diabetic FPG, 2 h PG, or HbA1c did not have a statistically significant association with albuminuria. These findings suggest that 1 h PG seems to be the best glycemic parameter and is useful in recognizing persons with an elevated risk of early kidney disease due to hyperglycemia.

Oxidative Stress and Left Ventricular Performance in Patients with Different Glycometabolic Phenotypes

The aim of the present study was to evaluate the possible correlation between oxidative stress and subclinical myocardial damage, assessed with speckle tracking echocardiography (STE), in normal glucose tolerance (NGT) patients with one-hour plasma glucose values ≥ 155 mg/dL (NGT ≥ 155), comparing them to NGT < 155 subjects, impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) newly diagnosed patients. We enrolled 100 Caucasian patients. All subjects underwent OGTT. The serum values of oxidative stress markers (8-isoprostane and Nox-2) were assessed with an ELISA test. Echocardiographic recordings were performed using an E-95 Pro ultrasound system. We observed significant differences, among the four groups, for fasting plasma glucose (p < 0.0001), one-hour postload (p < 0.0001), and two-hour postload plasma glucose (p < 0.0001). As compared with NGT < 155, NGT ≥ 155 exhibited significantly worse insulin sensitivity and higher values of hs-CRP. No significant differences were observed between NGT ≥ 155 and IGT patients. There was a significant increase in 8-isoprostane (p < 0.0001) and Nox-2 (p < 0.0001), from the first to fourth group, indicating an increase in oxidative stress with the worsening of the metabolic status. Serum levels of 8-isoprostane and Nox-2 were significantly increased in NGT ≥ 155 compared to the NGT < 155 group, but similar to IGT. The global longitudinal strain (GLS) appeared progressively lower proceeding from the NGT < 155 to T2DM group (p < 0.0001). For similar values of left ventricular ejection fraction (LVEF), NGT ≥ 155 exhibited reduced GLS compared to NGT < 155 (p = 0.001), but similar to IGT patients. Our study demonstrated that NGT ≥ 155 subjects exhibit early functional impairment of myocardial contractile fibres, these alterations are correlated with increased oxidative stress.