[Diagnostic accuracy of the tri-ponderal mass index in identifying the unhealthy metabolic obese phenotype in obese patients]

Introduction: The metabolically healthy obese (MHO) phenotype defines obese patients who have preserved insulin sensitivity and absence of metabolic complications. This phenotype is associated with a lower risk of cardiovascular disease and type2 diabetes in adulthood.

Objectives: To determine the prevalence of MHO and the metabolically unhealthy obesity (MUO) phenotype in a cohort of obese children and adolescents and to establish the predictive capacity of the tri-ponderal mass index (TMI) and other anthropometric parameters in order to identify these patients.

Patients and methods: A cross-sectional study was conducted on 239 obese patients (125males) from 8 to 18years of age. Grade3 obesity was present in 45.9% of the patients. ROC curves were used to find the best cut-off point for: TMI, body mass index (BMI), BMI z-score (BMIzs), and waist/height index (WHI). MHO components: plasma blood glucose, plasma triglycerides, HDL-cholesterol, and blood pressure.

Results: The prevalence of MUO in the study cohort was 62.4%. No differences between genders were observed, and it was increasing with the age and obesity degree. The TMI has a sensitivity of 75.8 and a specificity of 42.2 to identify the MUO patients. The best cut-off point for TMI is 18.7kg/m³, for BMI it was 30.4kg/m², for BMIzs +3.5SD, and 0.62 for WHI.

Conclusions: The diagnostic accuracy of TMI in identifying obese adolescents with metabolic risk was similar to BMI and WHI. However, the TMI is much simpler to use and simplifies the categorization of the obesity in both genders.