Original Article: Indices of insulin resistance in paediatric obesity

Background: Paediatric obesity is associated with insulin resistance (IR), which increases risk of type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD). Hyperinsulinaemic-euglycaemic clamp and minimal-model analysis frequently sampled intravenous glucose tolerance test (FSIVGTT) are used to assess IR, which are invasive, complex and expensive. Objective: To assess IR using the derived indices namely, homeostasis model assessment of insulin resistance (HOMAIR), fasting glucose-to-insulin ratio (FGIR), quantitative insulin-sensitivity check index (QUICKI), in obese children. Methods: Fifty obese children (cases) and 50 apparently healthy age-and gender- matched non- obese children (controls) were studied. Obese children with body mass index (BMI; Kg/m 2 ) greater than 95 th percentile and nonobese children with BMI between 5 th to 95 th percentile were included in the study. Results: Obese children had higher fasting insulin levels, HOMA-IR (p<0.001), FGIR (p<0.001) and QUICKI (p<0.001) when compared to controls; fasting blood glucose levels were comparable (p=0.170). A statistically significant correlation was observed between serum insulin and BMI, between insulin and all the derived indices and between the derived indices and BMI (p<0.001). HOMA-IR had more area under the curve (0.760) followed by FGIR (0.721) when compared to QUICKI (0.240). Conclusions: Obese children were normoglycaemic with IR. HOMA-IR was found to be a stronger predictor of IR when compared to FGIR and QUICKI in obese children.