HbA1c Cutoff for Prediabetes and Diabetes Based on Oral Glucose Tolerance Test in Obese Children and Adolescents

Diabetes screening outcomes in youth presenting for paediatric weight management: A report of the Paediatric Obesity Weight Evaluation Registry

OBJECTIVE

Rising prevalence of obesity has led to increased rates of prediabetes and diabetes mellitus (DM) in children. This study compares rates of prediabetes and diabetes using two recommended screening tests (fasting plasma glucose [FPG] and haemoglobin A1c [HbA1c]).

STUDY DESIGN

Data were collected prospectively from 37 multi-component paediatric weight management programs in POWER (Paediatric Obesity Weight Evaluation Registry).

RESULTS

For this study, 3962 children with obesity without a known diagnosis of DM at presentation and for whom concurrent measurement of FPG and HbA1c were available were evaluated (median age 12.0 years [interquartile range, IQR 9.8, 14.6]; 48% males; median body mass index 95th percentile [%BMIp95] 134% [IQR 120, 151]). Notably, 10.7% had prediabetes based on FPG criteria (100-125 mg/dL), 18.6% had prediabetes based on HbA1c criteria (5.7%-6.4%), 0.9% had DM by FPG abnormality (≥126 mg/dL) and 1.1% had DM by HbA1c abnormality (≥6.5%). Discordance between the tests was observed for youth in both age groups (10-18 years [n = 2915] and age 2-9 years [n = 1047]).

CONCLUSION

There is discordance between FPG and HbA1c for the diagnosis of prediabetes and DM in youth with obesity. Further studies are needed to understand the predictive capability of these tests for development of DM (in those diagnosed with prediabetes) and cardiometabolic risk.

Prevalence of prediabetes by the fasting plasma glucose and HbA1c screening criteria among the children and adolescents of Shenzhen, China

Background

Prediabetes is associated with an increased risk of cardiovascular diseases and all-cause mortality. Rare research in China has evaluated the prevalence of prediabetes among children and adolescents using the HbA1c criterion or the combined FPG-or-HbA1c diagnostic criterion, and researchers paid no attention to the distributions of blood glucose in Shenzhen, especially for juveniles.

Methods

We conducted a school-based cross-sectional study based on the first-year students from 17 primary, middle, and high schools. Prediabetes was defined as FPG of 5.6-6.9 mmol/L or HbA1c of 5.7%-6.4%. The crude and standardized prevalence of prediabetes with 95% confidence interval (95% CI) was estimated.

Results

A total of 7519 participants, aged 6 to 17 years, were included. For all subjects, the crude prevalence (95% CI) of prediabetes was 1.49% (1.21-1.77), 8.72% (8.08-9.36), and 9.80% (9.13-10.47) by the FPG-only, HbA1c-only, and FPG-or-HbA1c criteria, respectively. Based on the 2010 Shenzhen census population, the standardized prevalence was 1.56% (males 1.85%, females 1.19%), 11.05% (males 11.47%, females 10.53%), and 12.19% (males 13.01%, females 11.15%) by the corresponding criteria. The proportion of prediabetes was higher for males than females, and the prevalence decreased with grade for males but increased for females. The association of BMI and prediabetes was U-shaped curve, indicating higher rates of prediabetes for underweight and obesity people.

Conclusion

The blood glucose status of children and adolescents in Shenzhen is worrisome, and the early detection and management of prediabetes are imperative.

Prediabetes in children and adolescents: An updated review

Prediabetes, the precursor of type 2 diabetes mellitus, is an intermediate stage between normal glucose homeostasis and overt diabetes. This asymptomatic metabolic state is increasingly prevalent in pediatric population and is very difficult to detect without appropriate screening. Studies have shown that a certain proportion of children with prediabetes will develop diabetes in a few years. Even more alarming is the evidence that youth-onset diabetes has a more aggressive clinical course with progressive beta-cell decline and accelerated end-organ damage. Despite its importance, several aspects involving prediabetes in childhood are disputed or unknown. This review presents the latest insights into this challenging entity and outlines a simplified screening approach to aid clinical practice. In summary, childhood prediabetes is an important clinical condition indicating the need for proper screening and timely intervention.

Metabolic syndrome prevalence and impact on outcomes in patients with chronic graft-versus-host disease

Patients with chronic graft-versus-host disease (cGVHD) are at heightened risk for components of metabolic syndrome (MetS), yet the prevalence and impact of MetS in the cGVHD patient population remain unknown. Adult patients (n = 229) with cGVHD enrolled in the cross-sectional NIH cGVHD Natural History Study (NCT00092235) were evaluated for MetS at enrollment and for variables associated with MetS. A majority (54.1%, 124/229) of the cohort met the diagnostic criteria for MetS. Patients with higher body mass index and lower performance status scores were more likely to have MetS (P < 0.0001; P = 0.026; respectively). Higher circulating erythrocyte sedimentation rate, C-reactive protein, and creatinine concentrations, along with lower estimated glomerular filtration rate, were associated with MetS (P < 0.001; P < 0.004; P = 0.02; P = 0.002; respectively). Patients with MetS compared to patients without MetS had no statistical differences in survival or NRM (5-year OS: 64% [95% CI: 54.8-71.8%] vs. 75.1% [95% CI: 65.6-82.3%]; respectively; overall P = 0.20; 5-year NRM: 21.7% [95% CI: 13.6-30.9%] vs. 10.1% [95% CI: 4.4-18.7%]; respectively; overall P = 0.12). Additionally, there was no difference in cGVHD severity between the two groups. Given the high prevalence of MetS in this cohort, clinicians should screen for its presence before it develops into comorbidities that complicate the course of cGVHD treatment.

[Comparison of therapeutic effect of metformin hydrochloride/vildagliptin and liraglutide on type 2 diabetes mellitus in obese patients]

OBJECTIVE

To evaluate the therapeutic effects of two therapeutic strategies based on metformin hydrochloride/vildagliptin and liraglutide on type 2 diabetes mellitus (T2DM) in obese patients.

METHODS

We retrospectively collected the clinical data of 107 obese patients (BMI>25 kg/m2) with T2DM treated in Second Affiliated Hospital of Wannan Medical College (Wuhu, China) during 2019-2021, including 53 patients treated continuously with metformin hydrochloride/vildagliptin and 54 with liraglutide for 3 months. The changes in BMI, waist circumference, fasting blood glucose (FBG), postprandial blood glucose, HbA1C, fasting C-peptide, postprandial C-peptide, fasting insulin and postprandial insulin of the patients after treatment were compared between the two groups.

RESULTS

In both of the groups, the patients all showed significant reductions of BMI, waist circumference, FBG, postprandial blood glucose and HbA1C (all P < 0.05) with improved fasting and postprandial C-peptide levels after the treatments (P < 0.05). The two treatment regimens showed comparable blood glucoselowering effects, but liraglutide produced better effect in reducing waist circumference (P < 0.01). Neither of two regimens obviously affected insulin level of the patients (P>0.05).

CONCLUSION

Both metformin hydrochloride/vildagliptin and liraglutide have good therapeutic effects on T2DM in obese patients and can achieve good blood glucose and weight control, but liraglutide has a better effect for weight control.

Which Is the Most Appropriate Cut-Off of HbA1c for Prediabetes Screening in Caucasian Youths with Overweight or Obesity?

This cross-sectional study aimed to assess the best cut-off of HbA1c for detection of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), beta-cell impairment and cardiometabolic risk (CMR) profile in overweight or obese (OW/OB) Caucasian youths. Two-hour oral glucose tolerance test was available in 1549 youths, one-hour glucose (G₆₀) in 1430 youths and disposition index (DI) in 972 youths. Insulin resistance (IR) was calculated as Homeostatic Model Assessment for IR and insulin sensitivity (IS) as 1/fasting insulin. High G₆₀ was defined by a value ≥ 133 mg/dL. The best cut-off of HbA1c for IFG or IGT was 5.5%. The frequency of individuals with HbA1c ≥ 5.5% was 32.5%, compared to 16.3% with HbA1c ≥ 5.7% (as proposed by the American Diabetes Association). HbA1c ≥ 5.5% showed higher sensitivity and lower specificity with respect to HbA1c ≥ 5.7% for all the abnormalities examined (IFG, IGT, high G₆₀, IR, low IS, DI and CMR factors). In conclusion, this lower cut-off might represent a more appropriate screening marker of glucose dysmetabolism in youths with OW/OB. Prospective studies are needed to validate this cut-off for predicting prediabetes/diabetes in youths with OW/OB.

Cardiovascular Dysfunction in Intrauterine Growth Restriction

PURPOSE OF REVIEW

We highlight important new findings on cardiovascular dysfunction in intrauterine growth restriction.

RECENT FINDINGS

Intrauterine growth restriction (IUGR) is a multifactorial condition which negatively impacts neonatal growth during pregnancy and is associated with health problems during the lifespan. It affects 5-15% of all pregnancies in the USA and Europe with varying percentages in developing countries. Epidemiological studies have reported that IUGR is associated with the pathogenesis of hypertension, activation of the renin-angiotensin system (RAS), disruption in placental-mTORC and TGFβ signaling cascades, and endothelial dysfunction in IUGR fetuses, children, adolescents, and adults resulting in the development of cardiovascular diseases (CVD). Experimental studies are needed to investigate therapeutic measures to treat increased blood pressure (BP) and long-term CVD problems in people affected by IUGR. We outline the mechanisms mediating fetal programming of hypertension in developing CVD. We have reviewed findings from different experimental models focusing on recent studies that demonstrate CVD in IUGR.

Phenotypes of prediabetes and metabolic risk in Caucasian youths with overweight or obesity

PURPOSE

To assess the prevalence of pre-diabetes phenotypes, i.e., impaired fasting glucose (IFG), impaired glucose tolerance (IGT), increased HbA1c (IA1c), and their association with metabolic profile and atherogenic lipid profile in youths with overweight/obesity (OW/OB).

METHODS

This cross-sectional study analyzed data of 1549 youths (5-18 years) with OW/OB followed in nine Italian centers between 2016 and 2020. Fasting and post-load measurements of glucose, insulin, and HbA1c were available. Insulin resistance (IR) was estimated by HOMA-IR and insulin sensitivity (IS) by reciprocal of fasting insulin. The atherogenic lipid profile was assessed by triglycerides-to-HDL ratio or cholesterol-to-HDL ratio. Insulinogenic index was available in 939 youths, in whom the disposition index was calculated.

RESULTS

The prevalence of overall pre-diabetes, IFG, IGT and IA1c was 27.6%, 10.2%, 8% and 16.3%, respectively. Analyzing each isolated phenotype, IGT exhibited two- to three-fold higher odds ratio of family history of diabetes, and worse metabolic and atherogenic lipid profile vs normoglycemic youths; IFG was associated only with IR, while IA1c showed a metabolic and atherogenic lipid profile intermediate between IGT and IFG.

CONCLUSION

Prevalence of pre-diabetes was high and IA1c was the most prevalent phenotype in Italian youths with OW/OB. The IGT phenotype showed the worst metabolic and atherogenic lipid profile, followed by IA1c. More studies are needed to assess whether HbA1c may help improving the prediction of diabetes.

Oral glucose tolerance test: Ηow to maximize its diagnostic value in children and adolescents

BACKGROUND

Recently, the validity of the oral glucose tolerance test (OGTT) as a gold-standard test for the diagnosis of glucose dysregulation (GD) has been questioned due to the pre-analytical, analytical, and post-analytical variables which can potentially affect its reproducibility and accuracy.

AIMS

In this short update, the many  variables that affect the reproducibility and accuracy of the OGTT are described and discussed aiming to enhance its diagnostic value  in  clinical practice.

SEARCH STRATEGY

A systematic search was implemented in June 2022, using Scopus, PubMed, Embase and Google Scholar focusing on OGTT relevant  papers published in the last 10 years. Moreover,  the reference lists of these  articles were checked for additional pertinent studies. The research and selection of articles was also supported by the long-term authors' experience in the use of OGTT for the diagnosis of GD in children and adolescents.

CONCLUSION

The complexity of diagnosing GD presupposes that clinicians have specific knowledge and experience to perform rigorous assessment of glucose metabolism. It is worth mentioning that during OGTT, subjects with glucose levels  close to the cut-off values proposed  by WHO (World Health Organization)/ADA (American Diabetes Association) require careful evaluation in order to avoid misclassification and unnecessary interventions. For this reason, ADA recommends a second test to confirm the diagnosis of diabetes.

Who should return for an oral glucose tolerance test? A proposed clinical pathway based on retrospective analysis of 332 children

OBJECTIVES

Fasting plasma glucose or oral glucose tolerance test (OGTT) is the traditional diagnostic tool for type 2 diabetes (T2DM). However, fasting is required and implementation in all overweight/obese subjects is not practical. This study aimed to formulate a clinical pathway to stratify subjects according to their risk of abnormal OGTT.

METHODS

This retrospective study included patients with overweight or obesity who had undergone OGTT in a tertiary paediatric unit from 2012 to 2018. The optimal haemoglobin A1c (HbA1c) cutoff that predicts abnormal OGTT was evaluated. Other non-fasting parameters, in combination with this HbA1c cutoff, were also explored as predictors of abnormal OGTT.

RESULTS

Three hundred and thirty-two patients (boys: 54.2%, Chinese: 97.3%) were included for analysis, of which, 272 (81.9%) patients had normal OGTT while 60 (18.0%) patients had abnormal OGTT (prediabetes or T2DM). Optimal HbA1c predicting abnormal OGTT was 5.5% (AUC 0.71; sensitivity of 66.7% and specificity of 71%). When HbA1c≥5.5% was combined with positive family history and abnormal alanine transaminase (ALT) level, the positive predictive value for abnormal OGTT was increased from 33.6 to 61.6%.

CONCLUSIONS

HbA1c, family history of T2DM and ALT level could be used to derive a clinical pathway to stratify children who have high risk of abnormal OGTT.

Discordance between Fasting Plasma Glucose (FPG) and HbA1c in Diagnosing Diabetes and Pre-diabetes in The Malaysian Cohort

OBJECTIVE

In this present study, we aim to evaluate the accuracy of the HbA1c relative to fasting plasma glucose (FPG) in the diagnosis of diabetes and pre-diabetes among The Malaysian Cohort (TMC) participants.

METHODOLOGY

FPG and HbA1c were taken from 40,667 eligible TMC participants that have no previous history of diabetes, aged between 35-70 years and were recruited from 2006 - 2012. Participants were classified as normal, diabetes and pre-diabetes based on the 2006 World Health Organization (WHO) criteria. Statistical analyses were performed using ANOVA and Chi-square test, while Pearson correlation and Cohen's kappa were used to examine the concordance rate between FPG and HbA1c.

RESULTS

The study samples consisted of 16,224 men and 24,443 women. The prevalence of diabetes among the participants was 5.7% and 7.5% according to the FPG and HbA1c level, respectively. Based on FPG, 10.6% of the participants had pre-diabetes but this increased to 14.2% based on HbA1c (r=0.86; P<0.001). HbA1c had a sensitivity of 58.20 (95% CI: 56.43, 59.96) and a specificity of 98.59 (95% CI: 98.46, 98.70).

CONCLUSION

A higher prevalence of pre-diabetes and diabetes was observed when using HbA1c as a diagnosis tool, suggesting that it could possibly be more useful for early detection. However, given that HbA1c may also have lower sensitivity and higher false positive rate, several diagnostic criteria should be used to diagnose diabetes accurately.

[Prevalence of prediabetes and its comorbidities in the Mexican pediatric population]

Introduction

Background: prediabetes is a state observed before type-2 diabetes. Nowadays the obesity epidemic could be due to a rise in the incidence of prediabetes. Mexico has public policies for the management of non-communicable diseases. However, obesity rates continue to increase. The aim of this study was to elaborate on a diagnosis of prediabetes in the pediatric Mexican population, and compare the proportions of comorbidities that children with and without prediabetes had. Methods: a cross-sectional study was performed with 569 participants of 4 to 19 years of age from public schools. Anthropometric (weight, height, and waist circumference), clinical (blood pressure), and biochemical (fasting glucose, lipidic profile, and uric acid) variables were collected. Results: in all, 8.6 % of the population had prediabetes. Variables with the highest altered prevalence included triglycerides and systolic blood pressure. Boys had higher rates of prediabetes, altered BP, and hyperuricemia than girls. Children with prediabetes had a greater risk of elevated waist circumference, blood pressure, and uric acid measures. Conclusions: the Mexican pediatric population had elevated rates of prediabetes. Furthermore, the group with prediabetes had a higher risk of presenting high values of triglycerides, blood pressure, uric acid, and total cholesterol.

Update on the current modalities used to screen high risk youth for prediabetes and/or type 2 diabetes mellitus

The modalities currently employed to screen for type 2 diabetes mellitus (T2DM)/prediabetes are HbA1c, fasting plasma glucose (FPG), and 2-hour plasma glucose (PG) during an oral glucose tolerance test (OGTT). The purpose of this review is to highlight the positive qualities and pitfalls of these diagnostic modalities and reflect on the most reasonable and effective approach to screen high risk youth. Given its inherent preanalytical advantages, glycated hemoglobin (HbA1c) continues to be the preferred diagnostic modality used by pediatricians to screen high risk youth. However, when the three aforementioned tests are performed in youths of different races/ethnicities, discrepant results for T2DM/prediabetes are observed. The prevalence rates for T2DM vary from 0.53% in Chinese youth (including youth of all body mass indexes) to 18.3% in high-risk, overweight, obese Korean youth. Moreover, the FPG is abnormal (>100 less than <126 mg/dL) in 15% of Korean youth versus 8.7% of Chinese youth. The prevalence rates for prediabetes are 1.49% in Chinese youth versus 21% in Emirati youth (HbA1c, 5.7%-6.4%). The coefficient of agreement, k, between these screening tests for T2DM are fair, 0.45-0.5 across all youth. However, using HbA1c as a comparator, the agreement is weak with FPG (k=0.18 in German youth versus k=0.396 in Korean youth). The American Diabetes Association (ADA) Standards of Medical Care Guidelines define "high risk youth" who need to be tested for T2DM and/or prediabetes. OGTT and HbA1c do not always detect T2DM in similar individuals. HbA1c may not be an ideal test for screening Hispanic and African American youth. FPG and OGTT are suitable screening tests for youth of ethnic minorities and those with cystic fibrosis or hemoglobinopathies. Performing all three tests either together or sequentially may be the only way to encompass all youth who have aberrations in different aspects of glucose homeostasis.

Discrepancies between Glycosylated Hemoglobin and Fasting Plasma Glucose for Diagnosing Impaired Fasting Glucose and Diabetes Mellitus in Korean Youth and Young Adults

BACKGROUND

Glycosylated hemoglobin (HbA1c) has been recommended as a diagnostic test for prediabetes and diabetes. Here, we evaluated the level of agreement between diagnoses based on fasting plasma glucose (FPG) versus HbA1c levels and determined optimal HbA1c cutoff values for these diseases in youth and young adults.

METHODS

The study included 7,332 subjects (n=4,129, aged 10 to 19 years in youth group; and n=3,203 aged 20 to 29 years in young adult group) from the 2011 to 2016 Korea National Health and Nutrition Examination Survey. Prediabetes and diabetes were defined as 100 to 125 mg/dL (impaired fasting glucose [IFG]) and ≥126 mg/dL for FPG (diabetes mellitus [DM] by FPG [DM_FPG]), and 5.7% to 6.4% and ≥6.5% for HbA1c, respectively.

RESULTS

In the youth group, 32.5% with IFG had an HbA1c level of 5.7% to 6.4%, and 72.2% with DM_FPG had an HbA1c ≥6.5%. In the young adult group, 27.5% with IFG had an HbA1c level of 5.7% to 6.4%, and 66.6% with DM_FPG had an HbA1c ≥6.5%. Kappa coefficients for agreement between the FPG and HbA1c results were 0.12 for the youth group and 0.19 for the young adult group. In receiver operating characteristic curve analysis, the optimal HbA1c cutoff for IFG and DM_FPG were 5.6% and 5.9% in youths and 5.5% and 5.8% in young adults, respectively.

CONCLUSION

Usefulness of HbA1c for diagnosis of IFG and DM_FPG in Koreans aged <30 years remains to be determined due to discrepancies between the results of glucose- and HbA1c-based tests. Additional testing might be warranted at lower HbA1c levels to detect IFG and DM_FPG in this age group.