Diagnostic performance of insulin resistance indices and their association with metabolic outcomes in children with obesity: a 10-year retrospective study from a tertiary pediatric endocrinology center.
BACKGROUND Childhood obesity is strongly associated with insulin resistance (IR) and related metabolic complications. However, the optimal surrogate marker for identifying IR in pediatric populations remains unclear. OBJECTIVE To evaluate the diagnostic performance of commonly used IR indices and to investigate their association with metabolic outcomes in children and adolescents with obesity. METHODS This retrospective study included 899 children and adolescents with obesity followed at a tertiary pediatric endocrinology center over a 10-year period. IR was defined based on oral glucose tolerance test (OGTT) findings. The diagnostic performance of the fasting glucose-to-insulin ratio (FGIR), quantitative insulin sensitivity check index (QUICKI) and the homeostatic model assessment for insulin resistance (HOMA-IR) was assessed using receiver operating characteristic (ROC) curve analysis. Associations between IR, metabolic syndrome (MS), dysglycemia, hepatic steatosis, and biochemical parameters were analyzed. Multivariate logistic regression was performed to identify independent predictors. RESULTS HOMA-IR demonstrated the highest diagnostic performance for identifying IR (AUC: 0.711 in girls and 0.700 in boys), outperforming FGIR and QUICKI. Among pubertal participants, the optimal HOMA-IR cut-off values for predicting OGTT-defined insulin resistance were 4.22 in girls and 4.18 in boys. IR was present in 76.3% of participants and was associated with an unfavorable metabolic profile, including higher rates of dysglycemia and hepatic steatosis. Hepatic steatosis was detected in 63.5% of children and was significantly more common in boys. In multivariate analysis, male sex, BMI-SDS, and ALT were independent predictors of hepatic steatosis, whereas IR parameters were not independently associated. TSH levels were higher in IR and MS groups but remained within the normal range. CONCLUSION HOMA-IR is a reliable and practical marker for identifying IR in children with obesity. While IR is associated with multiple metabolic disturbances, adiposity and liver-related markers appear to play a more dominant role in predicting hepatic steatosis. A comprehensive metabolic evaluation, including both fasting indices and dynamic tests, is essential for early risk stratification in pediatric obesity.