Avaliação da estimativa da taxa de filtração glomerular com cistatina C em pacientes pediátricos

Abstract

Introduction : There have been national and international recommendations to estimate glomerular filtration rate as a predictor of kidney disease, in the general population, measuring plasma creatinine concentration. In pediatrics, however, there is a high incidence of factors that affect plasma creatinine concentration, such as growth rate and the equations most commonly used to estimate GFR are derivative from Bedside Schwartz formula. The serum cystatin C, an unglycosylated protein of low molecular weight, produced by all nucleated cells, has been proposed as a marker of glomerular filtration. In this context in Brazil, there have been doubts among professionals about using cystatin C in pediatrics, due to the lack of appropriate studies about it. Objective : We sought to investigate the transversal diagnostic accuracy, either related to cystatin C or plasma creatinine or both in comparison with inulin, for estimating changes in GFR in a prospective cohort of children with kidney disease. Patients and Methods : Firstly, we have chosen as methodological strategy for the estimation of GFR the measurement by inulin clearance, in pediatrics and in a young adult population, followed by a respective publication. Secondly, we have used repeated and simultaneous measurements of renal clearance by inulin in pediatric patients. The analysis has been performed by linear mixed model due to the number of repeated measurements from the same patient. In order to assess the equivalence between methods, we applied Bland & Altman graphics, as well as concordance correlation tests. In a second phase, we had cystatin C and serum creatinine measured in pediatric renal patients, including those patients who had undergone a transplant. Consequently, an article was submitted to publication and another one was submitted to analysis. Results : This thesis has generated four presentations at international scientific congresses, 4 articles and 1 book chapter in French (attached). Conclusions : The adequate measurement of GFR is of fundamental importance in clinical practice in all phases of one's life. The GFR progressively declines with time, in most renal diseases, which results in complications such as hypertension, anemia, malnutrition, bone disease, neuropathies.