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

Youth-onset Type 2 Diabetes: An Overview of Pathophysiology, Prognosis, Prevention and Management

PURPOSE OF REVIEW

This review explores the emerging evidence regarding pathogenesis, future trajectories, treatment options, and phenotypes of youth-onset type 2 diabetes (T2D).

RECENT FINDINGS

Youth-onset T2D is increasing in incidence and prevalence worldwide, disproportionately affecting First Nations communities, socioeconomically disadvantaged youth, and people of colour. Youth-onset T2D differs in pathogenesis to later-onset T2D and progresses more rapidly. It is associated with more complications, and these occur earlier. While there are limited licensed treatment options available, the available medications also appear to have a poorer response in youth with T2D. Multiple interacting factors likely contribute to this rising prevalence, as well as the increased severity of the condition, including structural inequities, increasing obesity and sedentary lifestyles, and intergenerational transmission from in-utero exposure to maternal hyperglycemia and obesity. Youth-onset T2D is also associated with stigma and poorer mental health, and these impact clinical management. There is an urgent need to develop effective interventions to prevent youth-onset T2D and enhance engagement of affected youth. It is also critical to better understand the differing phenotypes of youth-onset T2D, to effectively target treatments, and to address intergenerational transmission in high-risk populations.

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.

Utilizing the Glucose and Insulin Response Shape of an Oral Glucose Tolerance Test to Predict Dysglycemia in Children with Overweight and Obesity, Ages 8-18 Years

Common dysglycemia measurements including fasting plasma glucose (FPG), oral glucose tolerance test (OGTT)-derived 2 h plasma glucose, and hemoglobin A1c (HbA1c) have limitations for children. Dynamic OGTT glucose and insulin responses may better reflect underlying physiology. This analysis assessed glucose and insulin curve shapes utilizing classifications-biphasic, monophasic, or monotonically increasing-and functional principal components (FPCs) to predict future dysglycemia. The prospective cohort included 671 participants with no previous diabetes diagnosis (BMI percentile ≥ 85th, 8-18 years old); 193 returned for follow-up (median 14.5 months). Blood was collected every 30 min during the 2 h OGTT. Functional data analysis was performed on curves summarizing glucose and insulin responses. FPCs described variation in curve height (FPC1), time of peak (FPC2), and oscillation (FPC3). At baseline, both glucose and insulin FPC1 were significantly correlated with BMI percentile (Spearman correlation r = 0.22 and 0.48), triglycerides (r = 0.30 and 0.39), and HbA1c (r = 0.25 and 0.17). In longitudinal logistic regression analyses, glucose and insulin FPCs predicted future dysglycemia (AUC = 0.80) better than shape classifications (AUC = 0.69), HbA1c (AUC = 0.72), or FPG (AUC = 0.50). Further research should evaluate the utility of FPCs to predict metabolic diseases.

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.

One-Hour Post-Load Plasma Glucose and Altered Glucometabolic Profile in Youths with Overweight or Obesity

In youths, two cut-offs (133 and 155 mg/dL) have been proposed to identify high glucose levels at the 1 h (G60) mark during an oral glucose tolerance test (OGTT). We evaluated which cut-off was more closely associated with isolated impaired glucose tolerance (IGT) and cardiometabolic risk (CMR) in 1199 youth with overweight/obesity (OW/OB) and normal fasting glucose and/or HbA1c. The disposition index (DI) was available in 724 youths. The sample was divided by two cut-offs of G60: <133 mg/dL (n = 853) and ≥133 mg/dL (n = 346), or G60 < 155 mg/dL (n = 1050) and ≥155 mg/dL (n = 149). Independent of the cut-off, youths with high levels of G60 showed higher levels of G120, insulin resistance (IR), triglycerides to HDL ratio (TG/HDL), alanine aminotransferase (ALT), and lower insulin sensitivity (IS) and DI than youths with lower levels of G60. The percentage of youths showing IGT, IR, low IS, high TG/HDL ratio, high ALT, and low DI was 50% higher in the G60 ≥ 133 mg/dL group than in the G60 ≥ 155 mg/dL one. In youths with OW/OB and IGT, a cut-off of G60 ≥ 133 mg/dL is more useful than G60 ≥ 155 mg/dL to identify those at high risk of IGT and altered CMR profile.