Baseline level of 30-min plasma glucose is an independent predictor of incident diabetes among Asian Indians: analysis of two diabetes prevention programmes

Predisposition to Type 2 Diabetes in Aspects of the Glycemic Curve and Glycated Hemoglobin in Healthy, Young Adults: A Cross-sectional Study

OBJECTIVES

Our aim in this study was to identify predictors for diabetes among the characteristics of the glycemic curve and glycated hemoglobin (A1C) in healthy, young adults.

METHODS

We used a cross-sectional study to establish predictors for diabetes based on earlier studies and evaluated occurrence of the condition in 81 healthy, young adult subjects. These volunteers underwent analysis of fasting plasma glucose, oral glucose tolerance test plasma glucose, A1C, and inflammatory markers (leukocytes, monocytes, and C-reactive protein). The nonparametric Mann-Whitney U test, Fisher's exact test, chi-square test, Kruskal-Wallis test, and multiple-comparisons test were used to analyze the data.

RESULTS

We studied 2 age groups, homogeneous in terms of family history of diabetes: one group ranged in age from ≥18 to <28 years (median 20 years; body mass index [BMI] 24 kg/m2) and the other group ranged in age from ≥28 to <45 years (median 35 years; BMI 24 kg/m2). The older group had a higher incidence of predictors (p=0.0005) and was associated with the predictors 30-minute blood glucose ≥164 mg/dL (p=0.0190), 60-minute blood glucose ≥125 mg/dL (p=0.0346), and A1C ≥5.5% (p=0.0162), with a monophasic glycemic curve (p=0.007). The younger group was associated with the 2-hour plasma glucose predictor ≥140 mg/dL (p=0.014). All subjects had fasting glucose in the normal range.

CONCLUSIONS

Healthy, young adults may already have predictors of diabetes, identified mainly by aspects of the glycemic curve and A1C, but at more modest levels than those with prediabetes.

The Oral Glucose Tolerance Test: 100 Years Later

For over 100 years, the oral glucose tolerance test (OGTT) has been the cornerstone for detecting prediabetes and type 2 diabetes (T2DM). In recent decades, controversies have arisen identifying internationally acceptable cut points using fasting plasma glucose (FPG), 2-h post-load glucose (2-h PG), and/or HbA1c for defining intermediate hyperglycemia (prediabetes). Despite this, there has been a steadfast global consensus of the 2-h PG for defining dysglycemic states during the OGTT. This article reviews the history of the OGTT and recent advances in its application, including the glucose challenge test and mathematical modeling for determining the shape of the glucose curve. Pitfalls of the FPG, 2-h PG during the OGTT, and HbA1c are considered as well. Finally, the associations between the 30-minute and 1-hour plasma glucose (1-h PG) levels derived from the OGTT and incidence of diabetes and its complications will be reviewed. The considerable evidence base supports modifying current screening and diagnostic recommendations with the use of the 1-h PG. Measurement of the 1-h PG level could increase the likelihood of identifying high-risk individuals when the pancreatic ß-cell function is substantially more intact with the added practical advantage of potentially replacing the conventional 2-h OGTT making it more acceptable in the clinical setting.

30-minute postload plasma glucose levels during an oral glucose tolerance test predict the risk of future type 2 diabetes: the Hisayama Study

INTRODUCTION

To investigate the associations of 30 min postload plasma glucose (30 mPG) levels during an oral glucose tolerance test (OGTT) with the risk of future diabetes in a general Japanese population.

RESEARCH DESIGN AND METHODS

A total of 2957 Japanese community-dwelling residents without diabetes, aged 40-79 years, participated in the examinations in 2007 and 2008 (participation rate, 77.1%). Among them, 2162 subjects who received 75 g OGTT in a fasting state with measurements of plasma glucose level at 0, 30, and 120 min were followed up for 7 years (2007-2014). Cox's proportional hazards model was used to estimate HRs and their 95% CIs of each index for the development of type 2 diabetes using continuous variables and quartiles with adjustment for traditional risk factors. The influence of 30 mPG on the predictive ability was estimated with Harrell's C-statistics, integrated discrimination improvement (IDI), and the continuous net reclassification index (cNRI).

RESULTS

During follow-up, 275 subjects experienced type 2 diabetes. Elevated 30 mPG levels were significantly associated with increased risk of developing diabetes (p<0.01 for trend): the multivariable-adjusted HR was 8.41 (95% CI 4.97 to 14.24) for the highest versus the lowest quartile, and 2.26 (2.04 to 2.52) per 1 SD increase. This association was attenuated but remained significant after further adjustment for fasting and 2-hour postload plasma glucose levels. Incorporation of 30 mPG into the model including traditional risk factors with fasting and 2-hour postload plasma glucose levels for diabetes improved the predictive ability of type 2 diabetes (improvement in Harrell's C-statistics values: from 0.828 to 0.839, p<0.01; IDI: 0.016, p<0.01; cNRI: 0.103, p=0.37).

CONCLUSIONS

Elevated 30 mPG levels were associated with increased risk of diabetes, and inclusion of 30 mPG levels significantly improved the predictive ability for future diabetes, suggesting that 30 mPG may be useful for identifying high-risk populations for type 2 diabetes.

Clinical utility of 30-min plasma glucose for prediction of type 2 diabetes among people with prediabetes: Ancillary analysis of the diabetes community lifestyle improvement program

AIMS

To examine the clinical utility of 30-min plasma glucose (30-min-PG) measurement during an oral glucose tolerance (OGTT) in predicting type 2 diabetes (T2DM).

RESEARCH DESIGN AND METHODS

Data from a 3-year, randomized, controlled, primary prevention trial among 548 Asian Indians with prediabetes were analyzed. Participants underwent OGTT with PG measurements at fasting, 30-min, and 2-h at baseline and annually until the end of the study. Multivariable Cox regression models were constructed to calculate the risk of developing diabetes based on 30-min-PG levels. Improvement in prediction performance gained by adding an elevated level of 30-min-PG over prediabetic categories was calculated using the area-under-curve (AUC), net-reclassification (NRI), and integrated discrimination improvement (IDI) statistics.

RESULTS

At the end of follow-up, 30.4% of individuals had been diagnosed with T2DM by ADA criteria. Based on the maximally selected log-rank statistics, the optimal 30-min-PG cut point for predicting incident T2DM was >182 mg/dl. Multivariable-adjusted Cox regression models showed an independent association between elevated 30-min-PG (>182 mg/dl) and incident diabetes (hazard ratio (95% CI): 1.85 [1.32, 2.59]; D_xy = 0.353, c-statistic = 0.676). The addition of an elevated 30-min-PG (>182 mg/dl) model significantly improved the prediction of diabetes (Δdeviance: -15.4; ΔAUC: 0.11; NRI_continuous: 0.51; IDI: 0.08) compared with IFG model alone) in individuals with prediabetes.

CONCLUSION

In prediabetic individuals, baseline 30-min-PG independently predicted T2DM and significantly improved reclassification and discrimination. Therefore, 30-min-PG should be considered as part of the routine testing in addition to FPG and 2-h-PG for better risk stratification.

Development of type 2 diabetes mellitus in people with intermediate hyperglycaemia

BACKGROUND

Intermediate hyperglycaemia (IH) is characterised by one or more measurements of elevated blood glucose concentrations, such as impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and elevated glycosylated haemoglobin A1c (HbA1c). These levels are higher than normal but below the diagnostic threshold for type 2 diabetes mellitus (T2DM). The reduced threshold of 5.6 mmol/L (100 mg/dL) fasting plasma glucose (FPG) for defining IFG, introduced by the American Diabetes Association (ADA) in 2003, substantially increased the prevalence of IFG. Likewise, the lowering of the HbA1c threshold from 6.0% to 5.7% by the ADA in 2010 could potentially have significant medical, public health and socioeconomic impacts.

OBJECTIVES

To assess the overall prognosis of people with IH for developing T2DM, regression from IH to normoglycaemia and the difference in T2DM incidence in people with IH versus people with normoglycaemia.

SEARCH METHODS

We searched MEDLINE, Embase, ClincialTrials.gov and the International Clinical Trials Registry Platform (ICTRP) Search Portal up to December 2016 and updated the MEDLINE search in February 2018. We used several complementary search methods in addition to a Boolean search based on analytical text mining.

SELECTION CRITERIA

We included prospective cohort studies investigating the development of T2DM in people with IH. We used standard definitions of IH as described by the ADA or World Health Organization (WHO). We excluded intervention trials and studies on cohorts with additional comorbidities at baseline, studies with missing data on the transition from IH to T2DM, and studies where T2DM incidence was evaluated by documents or self-report only.

DATA COLLECTION AND ANALYSIS

One review author extracted study characteristics, and a second author checked the extracted data. We used a tailored version of the Quality In Prognosis Studies (QUIPS) tool for assessing risk of bias. We pooled incidence and incidence rate ratios (IRR) using a random-effects model to account for between-study heterogeneity. To meta-analyse incidence data, we used a method for pooling proportions. For hazard ratios (HR) and odds ratios (OR) of IH versus normoglycaemia, reported with 95% confidence intervals (CI), we obtained standard errors from these CIs and performed random-effects meta-analyses using the generic inverse-variance method. We used multivariable HRs and the model with the greatest number of covariates. We evaluated the certainty of the evidence with an adapted version of the GRADE framework.

MAIN RESULTS

We included 103 prospective cohort studies. The studies mainly defined IH by IFG5.6 (FPG mmol/L 5.6 to 6.9 mmol/L or 100 mg/dL to 125 mg/dL), IFG6.1 (FPG 6.1 mmol/L to 6.9 mmol/L or 110 mg/dL to 125 mg/dL), IGT (plasma glucose 7.8 mmol/L to 11.1 mmol/L or 140 mg/dL to 199 mg/dL two hours after a 75 g glucose load on the oral glucose tolerance test, combined IFG and IGT (IFG/IGT), and elevated HbA1c (HbA1c5.7: HbA1c 5.7% to 6.4% or 39 mmol/mol to 46 mmol/mol; HbA1c6.0: HbA1c 6.0% to 6.4% or 42 mmol/mol to 46 mmol/mol). The follow-up period ranged from 1 to 24 years. Ninety-three studies evaluated the overall prognosis of people with IH measured by cumulative T2DM incidence, and 52 studies evaluated glycaemic status as a prognostic factor for T2DM by comparing a cohort with IH to a cohort with normoglycaemia. Participants were of Australian, European or North American origin in 41 studies; Latin American in 7; Asian or Middle Eastern in 50; and Islanders or American Indians in 5. Six studies included children and/or adolescents.Cumulative incidence of T2DM associated with IFG5.6, IFG6.1, IGT and the combination of IFG/IGT increased with length of follow-up. Cumulative incidence was highest with IFG/IGT, followed by IGT, IFG6.1 and IFG5.6. Limited data showed a higher T2DM incidence associated with HbA1c6.0 compared to HbA1c5.7. We rated the evidence for overall prognosis as of moderate certainty because of imprecision (wide CIs in most studies). In the 47 studies reporting restitution of normoglycaemia, regression ranged from 33% to 59% within one to five years follow-up, and from 17% to 42% for 6 to 11 years of follow-up (moderate-certainty evidence).Studies evaluating the prognostic effect of IH versus normoglycaemia reported different effect measures (HRs, IRRs and ORs). Overall, the effect measures all indicated an elevated risk of T2DM at 1 to 24 years of follow-up. Taking into account the long-term follow-up of cohort studies, estimation of HRs for time-dependent events like T2DM incidence appeared most reliable. The pooled HR and the number of studies and participants for different IH definitions as compared to normoglycaemia were: IFG5.6: HR 4.32 (95% CI 2.61 to 7.12), 8 studies, 9017 participants; IFG6.1: HR 5.47 (95% CI 3.50 to 8.54), 9 studies, 2818 participants; IGT: HR 3.61 (95% CI 2.31 to 5.64), 5 studies, 4010 participants; IFG and IGT: HR 6.90 (95% CI 4.15 to 11.45), 5 studies, 1038 participants; HbA1c5.7: HR 5.55 (95% CI 2.77 to 11.12), 4 studies, 5223 participants; HbA1c6.0: HR 10.10 (95% CI 3.59 to 28.43), 6 studies, 4532 participants. In subgroup analyses, there was no clear pattern of differences between geographic regions. We downgraded the evidence for the prognostic effect of IH versus normoglycaemia to low-certainty evidence due to study limitations because many studies did not adequately adjust for confounders. Imprecision and inconsistency required further downgrading due to wide 95% CIs and wide 95% prediction intervals (sometimes ranging from negative to positive prognostic factor to outcome associations), respectively.This evidence is up to date as of 26 February 2018.

AUTHORS' CONCLUSIONS

Overall prognosis of people with IH worsened over time. T2DM cumulative incidence generally increased over the course of follow-up but varied with IH definition. Regression from IH to normoglycaemia decreased over time but was observed even after 11 years of follow-up. The risk of developing T2DM when comparing IH with normoglycaemia at baseline varied by IH definition. Taking into consideration the uncertainty of the available evidence, as well as the fluctuating stages of normoglycaemia, IH and T2DM, which may transition from one stage to another in both directions even after years of follow-up, practitioners should be careful about the potential implications of any active intervention for people 'diagnosed' with IH.

Body composition analysis, anthropometric indices and lipid profile markers as predictors for prediabetes

OBJECTIVES

To compare different anthropometric indices, Body composition analysis and lipid profile markers in terms of their ability to predict prediabetes (PD).

METHODS

We enrolled 83 subjects with PD and 84 normoglycemic subjects who were matched for age and gender. The diagnosis of prediabetes was done according to the American Diabetes Association (ADA) criteria. All subjects were aged between 30-55 years of age and visited the outpatient department of tertiary care hospital. Anthropometric and lipid profile measurements were obtained. Analysis of body composition was done using Bodystat 1500MDD Instrument. Backward logistic regression was performed for detecting the predictors of PD. A receiver operator characteristic curve (ROC) with area under curve (AUC) was utilized for the accuracy of the predictors of PD.

RESULTS

Comparison of anthropometric measurement and body composition analysis parameters between the two groups showed that Waist circumference (WC), Body mass index, Body Fat% were significantly higher whereas Extracellular water and Dry lean weight in percentage (ECW% and DLW%) were found to be lower in PD (p< 0.05). Higher triglyceride (TG) levels and lower high-density cholesterol (HDL-C) with high TG/HDL-C were seen in subjects with PD. Backward logistic regression analysis found the combination of Body Fat % with WC, TG, ECW% and DLW% as strong predictors of PD. In ROC analysis, ECW% (AUC = 0.703) was the most predictive measure, followed by WC (AUC = 0.702).

CONCLUSION

This study demonstrated that estimation of Body Fat % combined with waist circumference, Extracellular water and Dry lean weight in percentage are valuable in screening and diagnosis of prediabetes. Plasma levels of TG in lipid profile measurements can also serve as an additional marker for prediction of prediabetes.

The effects of Jerusalem artichoke and fermented soybean powder mixture supplementation on blood glucose and oxidative stress in subjects with prediabetes or newly diagnosed type 2 diabetes

BACKGROUND/OBJECTIVES

The objective of this study was to evaluate the effect of supplementation with a Jerusalem artichoke and fermented soybean powder mixture on blood glucose and oxidative stress levels.

SUBJECTS/METHODS

This randomized, double-blinded, placebo-controlled study was conducted on 60 subjects with impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or newly diagnosed type 2 diabetes. The subjects were randomly assigned to either a group that ingested 40 g of a Jerusalem artichoke and fermented soybean powder mixture (19.45 g each) daily or a group that received a placebo for 12 weeks. Paired t-test and independent t-test were performed for comparisons within groups and between groups, respectively.

RESULTS

Supplementation with the Jerusalem artichoke and fermented soybean powder mixture reduced the levels of fasting glucose (p < 0.001) and FFAs (p = 0.034), glucose at 60 min (p = 0.004), glucose (p = 0.006) areas under the response curve (AUC), homeostasis model assessment-insulin resistance (p = 0.018), and the urinary 8-epi-prostaglandin F2α (8-epi-PGF2α) level (p = 0.028). The changes (Δ) in urinary 8-epi-PGF2α, glucose at 60 min, 120 min, and AUC, FFAs at 0 min and AUC were significantly different between the two groups. In addition, Δ glucose at 120 min (r = 0.472, p = 0.027) and the Δ glucose AUC (r = 0.572, p = 0.005) were positively correlated with △ plasma malondialdehyde in the test group.

CONCLUSIONS

The consumption of a Jerusalem artichoke and fermented soybean powder mixture for 12 weeks was effective for reducing postprandial glucose and oxidative stress level, particularly 8-epi-PGF2α, in subjects with IFG, IGT, or newly diagnosed type 2 diabetes.

Association of serum orosomucoid with 30-min plasma glucose and glucose excursion during oral glucose tolerance tests in non-obese young Japanese women

OBJECTIVE

Inflammatory markers are elevated in insulin resistance (IR) and diabetes. We tested whether serum orosomucoid (ORM) is associated with postload glucose, β-cell dysfunction and IR inferred from plasma insulin kinetics during a 75 g oral glucose tolerance test (OGTT).

RESEARCH DESIGN AND METHODS

75 g OGTTs were performed with multiple postload glucose and insulin measurements over a 30-120 min period in 168 non-obese Japanese women (aged 18-24 years). OGTT responses, serum adiponectin and high-sensitivity C reactive protein (hsCRP) were cross-sectionally analyzed by analysis of variance and then Bonferroni's multiple comparison procedure. Stepwise multivariate linear regression analyses were used to identify most important determinants of ORM.

RESULTS

Of 168 women, 161 had normal glucose tolerance. Postload glucose levels and the area under the glucose curve (AUCg) increased in a stepwise fashion from the first through the third ORM tertile. In contrast, there was no or modest, if any, association with fat mass index, trunk/leg fat ratio, adiponectin, hsCRP, postload insulinemia, the Matsuda index and homeostasis model assessment IR. In multivariable models, which incorporated the insulinogenic index, the Matsuda index and HOMA-IR, 30 min glucose (standardized β: 0.517) and AUCg (standardized β: 0.495) explained 92.8% of ORM variations.

CONCLUSIONS

Elevated circulating orosomucoid was associated with elevated 30 min glucose and glucose excursion in non-obese young Japanese women independently of adiposity, IR, insulin secretion, adiponectin and other investigated markers of inflammation. Although further research is needed, these results may suggest a clue to identify novel pathways that may have utility in monitoring dysglycemia within normal glucose tolerance.

Time to glucose peak during an oral glucose tolerance test identifies prediabetes risk

CONTEXT

Morphological characteristics of the glucose curve during an oral glucose tolerance test (OGTT) (time to peak and shape) may reflect different phenotypes of insulin secretion and action, but their ability to predict diabetes risk is uncertain.

OBJECTIVE

To compare the ability of time to glucose peak and curve shape to detect prediabetes and β-cell function.

DESIGN AND PARTICIPANTS

In a cross-sectional evaluation using an OGTT, 145 adults without diabetes (age 42±9 years (mean±SD), range 24-62 years, BMI 29.2±5.3 kg/m² , range 19.9-45.2 kg/m² ) were characterized by peak (30 minutes vs >30 minutes) and shape (biphasic vs monophasic).

MAIN OUTCOME MEASURES

Prediabetes and disposition index (DI)-a marker of β-cell function.

RESULTS

Prediabetes was diagnosed in 36% (52/145) of participants. Peak>30 minutes, not monophasic curve, was associated with increased odds of prediabetes (OR: 4.0 vs 1.1; P<.001). Both monophasic curve and peak>30 minutes were associated with lower DI (P≤.01). Time to glucose peak and glucose area under the curves (AUC) were independent predictors of DI (adjR² =0.45, P<.001).

CONCLUSION

Glucose peak >30 minutes was a stronger independent indicator of prediabetes and β-cell function than the monophasic curve. Time to glucose peak may be an important tool that could enhance prediabetes risk stratification.

Glucose patterns during the OGTT and risk of future diabetes in an urban Indian population: The CARRS study

AIMS

Traditionally, fasting and 2-hour post challenge plasma glucose have been used to diagnose diabetes. However, evidence indicates that clinically relevant pathophysiological information can be obtained by adding intermediate time-points to a standard oral glucose tolerance test (OGTT).

METHODS

We studied a population-based sample of 3666 Asian Indians without diabetes from the CARRS-Chennai Study, India. Participants underwent a three-point (fasting, 30-min, and 2-h) OGTT at baseline. Patterns of glycemic response during OGTT were identified using latent class mixed-effects models. After a median follow-up of two years, participants had a second OGTT. Logistic regression adjusted for diabetes risk factors was used to compare risk of incident diabetes among participants in different latent classes.

RESULTS

We identified four latent classes with different glucose patterns (Classes 1-4). Glucose values for Classes 1, 2, and 4 ranked consistently at all three time-points, but at gradually higher levels. However, Class 3 represented a distinct pattern, characterized by high 30-min (30minPG), normal fasting (FPG) and 2-h (2hPG) plasma glucose, moderately high insulin sensitivity, and low acute insulin response. Approximately 22% of participants were categorized as Class 3, and had a 10-fold risk of diabetes compared to the group with the most favorable glucose response, despite 92.5% of Class 3 participants having normal glucose tolerance (NGT) at baseline.

CONCLUSIONS

Elevated 30minPG is associated with high risk of incident diabetes, even in individuals classified as NGT by a traditional OGTT. Assessing 30minPG may identify a subgroup of high-risk individuals who remained unidentified by traditional measures.

One-hour post-load plasma glucose level during the OGTT predicts dysglycemia: Observations from the 24year follow-up of the Israel Study of Glucose Intolerance, Obesity and Hypertension

AIMS

The present study assessed the longitudinal association of an elevated 1-h plasma glucose [1-h-PG >8.6mmol/l (155mg/dl)] with and without impaired glucose tolerance [IGT; 2-h-PG 7.8-11.0mmol/l (140-199mg/dl)] with cumulative incident of diabetes and prediabetes over 24years in a non-diabetic cohort.

METHODS

From 1979 to 1984, 1970 non-diabetic men and women completed an oral glucose tolerance test (OGTT), physical and biochemical measurements as well as a questionnaire related to lifestyle and medical background. During the years 2000-2004, 853 survivors of the original cohort were interviewed and re-examined for glycemic progression.

RESULTS

Individuals with 1-h-PG >8.6mmol/l (155mg/dl) but with 2-h-PG <7.8mmol/l (140mg/dl) had a significantly elevated risk, compared to those with both 1-h-PG ⩽8.6mmol/l (155mg/dl) and 2-h-PG <7.8mmol/l (140mg/dl), for both diabetes [OR:4.35 (95%CI: 2.50-7.73)] and prediabetes outcomes [OR:1.87 (95%CI 1.09-3.26)], adjusted for sex and age, smoking, body mass index, blood pressure, fasting blood glucose and insulin.

CONCLUSIONS

The risk for diabetes associated with a 1-h level >8.6mmol/l (155mg/dl) is increased and further worsened in the presence of IGT. Identifying individuals at risk with a 1-h-PG glucose level during an OGTT is recommended.