The incidence of insulin resistance based on indices calculated using the HOMA and Belfiore methods and its impact on the occurrence of metabolic complications in prepubertal children born small for gestational age

INTRODUCTION: Children born small for gestational age (SGA) are predisposed to obesity, insulin resistance (IR), and lipid disorders. The HOMA-IR index is commonly used to assess IR (IRI(HOMA)), calculated from fasting glucose and insulin. However, sometimes, during the oral glucose tolerance test (OGTT), elevated and prolonged postprandial insulin secretion is observed despite normal fasting insulin levels. IRI(Belfiore) is an IR index that analyses glucose and insulin levels during OGTT according to the method proposed by Belfiore. THE AIM OF THE STUDY: was to assess the frequency of IR based on IRI(HOMA) and IRI(Belfiore) results in SGA children aged 6–8 years, after catch-up phenomenon, to determine the usefulness of IRI(Belfiore) in diagnosis of IR and in predicting future metabolic complications. MATERIAL AND METHODS: In 129 SGA normal-height children, aged 6–8 years, height, weight, waist circumference, blood pressure, as well as lipids, IGF-1, cortisol, C-peptide, leptin, adiponectin, and resistin concentrations were measured. The glucose and insulin concentrations were evaluated at 0, 60, and 120 minutes of OGTT. RESULTS: IRI(HOMA) was normal in all children, while elevated IRI(Belfiore) was found in 22.5% of them. Children with IR diagnosed by IRI(Belfiore) were taller, had higher blood pressure, higher leptin, and lower HDL-cholesterol concentrations. CONCLUSIONS: It seems worth recommending IRI(Belfiore) derived from OGTT as a valuable diagnostic tool for identifying IR in SGA prepubertal children. Abnormal IRI(Belfiore) is related to higher blood pressure and lower HDL-cholesterol concentration in this group.