Metabolic syndrome in obese adolescents: a comparison of three different diagnostic criteria.

OBJECTIVE To investigate the difference in the proportion of adolescents with metabolic syndrome diagnosed based on three different criteria, as well as the use of insulin resistance instead of fasting glucose. METHODS Cross-sectional study with 121 obese adolescents, between 10 and 14 years old, from public schools of the city of Porto Alegre, Brazil, in 2011. Anthropometric, blood pressure, and biochemical variables were assessed. Metabolic syndrome was defined using three different diagnostic criteria: the International Diabetes Federation (IDF), Cook and de Ferranti. All of them include five components: waist circumference, blood pressure, high-density lipoprotein (HDL) cholesterol, triglycerides and fasting glucose, and there should be at least three abnormal results for the diagnosis of the syndrome. The Homeostasis Model Assessment - Insuline Resistance (HOMA-IR) was used for the characterization of insulin resistance. The analysis of agreement among the criteria was performed using Kappa statistics. RESULTS Metabolic syndrome was diagnosed in 39.7, 51.2, and 74.4% of adolescents, according to the IDF, Cook and de Ferranti criteria, respectively. There was agreement for the three diagnostic criteria in 60.3% of the sample. Waist circumference was the most prevalent component (81.0, 81.0, and 96.7%), whereas high fasting glucose was the least prevalent (7.4, 1.7, and 1.7%). The use of HOMA-IR significantly increased the proportion of positive diagnoses for the syndrome. CONCLUSION The results showed significant differences between the three diagnostic criteria. While there is no consensus on the diagnostic criteria for metabolic syndrome, differences in the prevalence of the disease in pediatric population will be frequent.