The Role of Haemoglobin A1c in Screening Obese Children and Adolescents for Glucose Intolerance and Type 2 Diabetes

Júlia Galhardo, Julian Shield

Abstract


Introduction: In 2012, an international expert committee in diabetes wrote in favor of screening adult and paediatric patients for glucose intolerance and type 2 diabetes using glycated haemoglobin. The aim of this study was to evaluate glycated haemoglobin utility as a screening tool in a young obese mainly Caucasian population.
Material and Methods: Children [(n = 266), body mass index z-score 3.35 ± 0.59, 90% Caucasian 90%, 55% female, median age 12.3 (range: 8.9 - 17.6) years old] recently referred to a tertiary hospital-based obesity clinic underwent a routine oral glicose tolerance test and glycated haemoglobin measurement. Exclusion criteria: abnormal forms of haemoglobin and conditions linked to increased erythrocyte turnover.
Results: The oral glicose tolerance test diagnosed 13 (4.9%) subjects as prediabetic but none as diabetic. According to glycated haemoglobin, 32 would be prediabetic (29 false positives) and one would be diabetic (when he was only glucose intolerant). On the other hand, 10 prediabetic patients would not have been identified (false negatives). Glycated haemoglobin receiver operator characteristic analysis area under the curve was 0.59 (CI 95% 0.40 - 0.78), confirming its reduced capacity to identify prediabetes. Better results were achieved when calculating receiver operator characteristic analysis area under the curve for fasting glucose (0.76;
CI 95% 0.66 - 0.87), homeostasis model assessment for insulin resistance (0.77; CI 95% 0.64 - 0.90) and triglycerides:HDL cholesterol ratio (0.81; CI 95% 0.66 - 0.96).
Discussion: In Paediatric populations, especially when mainly Caucasian, glycated haemoglobin does not seem to be a useful
screening tool for prediabetes.
Conclusion: For this reason, it would appear premature to advise it as a diagnostic tool until significantly more data is available. Homeostasis model assessment for insulin resistance and triglycerides: HDL cholesterol have higher precision and can be calculated using a fasting blood sample.

Keywords


Adolescent; Child; Diabetes Mellitus, Type 2; Glucose Intolerance; Haemoglobin A, Glycosylated; Mass Screening; Obesity; Pediatric Obesity.

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