O Papel da Hemoglobina A1c no Rastreio de Intolerância à Glicose e da Diabetes Tipo 2 em Crianças e Adolescentes Obesos

Abstract

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. 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. abnormal forms of haemoglobin and conditions linked to increased erythrocyte turnover. 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). In Paediatric populations, especially when mainly Caucasian, glycated haemoglobin does not seem to be a useful screening tool for prediabetes. 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.