Fasting Biomarkers and Glycated Haemoglobin Identify Children With Excess Weight at Risk of Dysglycaemia and Guide Oral Glucose Tolerance Testing

AIM: Childhood obesity has been strongly associated with insulin resistance and dysglycaemia. We aimed to evaluate fasting biomarkers and glycated haemoglobin (HbA1c) for identifying children at risk and guiding the need for oral glucose tolerance testing (OGTT). METHODS: This single-centre study included 475 consecutive children aged 5-18 years with excess weight who underwent OGTT. Insulin resistance and dysglycaemia were defined based on OGTT-derived indices. Fasting glucose (FG), fasting insulin (FI), homeostatic model assessment of insulin resistance (HOMA-IR), homeostatic model assessment of β-cell function (HOMA-β), and HbA1c were evaluated. Receiver operating characteristic (ROC) analysis was used to determine optimal cut-offs for predicting dysglycaemia. RESULTS: The cohort comprised 281 girls (59.2%) and 194 boys, with a median age of 13.8 years. Insulin resistance was present in 81.5% (387/475) and dysglycaemia in 18.9% (90/475). FG above the 90th percentile, FI and HOMA-IR above the 97.5th percentile, and HbA1c ≥ 39 mmol/mol (5.7%) were significantly associated with dysglycaemia (p < 0.05). ROC analysis for the entire cohort identified FG 5.27 mmol/L, HbA1c 39 mmol/mol, and HOMA-IR 4.88 as significant cut-offs (all p < 0.001). CONCLUSION: Fasting biomarkers and HbA1c identified children with excess weight at risk of dysglycaemia, providing practical thresholds to guide the need for OGTT.