PROPOSTA DE PONTO DE CORTE DO ÍNDICE DE MASSA CORPORAL (IMC) PARA DIAGNÓSTICO DE OBESIDADE EM TRANSPLANTADOS RENAIS: COMPARAÇÃO COM MÉTODO PADRÃO OURO

Abstract

Introduction: Individuals with kidney transplant (KTR) show high incidence of obesity together with the increase of total body mass. Body mass index (BMI) ) is a universally used method for nutritional assessment and classifies obesity values ≥30 kg / m², but it does not identify the body composition. This cutoff point has been defined for healthy population and therefore may not be appropriate for assessing obesity in kidney transplant patients. Objective: State a cohort point of BMI for the diagnosis of obesity in KTR patients, through the analysis of sensitivity and specificity of BMI with body adiposity, which is gotten through the golden standard Air Displacement Plethysmography (PDA) method. Methods: Cross sectional study with 122 individuals with KTR, from the whole state of Maranhão, who were treated in the Center of Prevention of Kidney Diseases at the University Hospital at the Federal University of Maranhão. Through BMI, weight and height were measured for the evaluation of individuals’ nutritional conditions, and %BF was estimated using ADP (BOD POD – COSMED®, Italy). In order to evaluate the diagnostic performance of BMI in the detection of high %BF, the analysis ROC (Receiver Operating Characteristic) was used. The precision of the diagnosis refers to the ability of BMI to discriminate individuals with high %BF, and the ones with normal or low %BF. In order so, AUC (Area Under the ROC Curve) were determined. Then, there were calculated the sensitiveness and specificity between BMI and %BF that had been gained by ADP. The demonstrated values, which constitute cohort points, were the ones that showed more appropriate balance between sensitiveness and specificity for BMI. The adopted significance level was of 5%. The analyses were done at STATA 14.0®. Results: The mean age of the 122 individuals with kidney transplant was of 43,4±10,0 years. There was prevalence of overweight and obesity by BMI was 38,5% and 14,8% respectively, and 54,1% of high %BF by ADP. Cohort points of BMI for individuals with kidney transplant were: 25,0 kg/m2 for men (sensitiveness: 80,8%; specificity: 80,0%) and 23,0 kg/m2 for women (sensitiveness: 95,0%: specificity: 81,2%). Conclusion: It is likely that the use of BMI with suggested cohort points will contribute to an early diagnosis of obesity in TxR patients, allowing immediate intervention, prevent complications, increase the graft’s lifetime and reducing levels of mortality.