Francois Cachat
University of Bern, Inselspital, Switzerland
Title: Microalbuminuria in children with nephro-urological disorders does not indicate glomerular hyperfiltration
Biography
Biography: Francois Cachat
Abstract
Background Microalbuminuria (MA) has been shown to be an early biomarker of renal damage. It is postulated that MA is the early result of hyperfiltration, which could evolve into glomerular sclerosis and renal failure if hyperfiltration is left untreated. We hypothesized that MA is a good indicator of hyperfiltration in children with kidney disorders, obviating the need to calculate the filtration fraction (FF). Methods 155 children or young adults were prospectively included [42 single kidney (SK), 61 vesicoureteral reflux, 23 obstructive uropathies, 29 other kidney diseases]. We measured inulin, para-aminohippuric acid clearances, FF and MA. Prediction of hyperfiltration was explored by studying the association between FF and other variables such as urinary albumin (Alb), urinary albumin–creatinine ratio (ACR), creatinine clearance. Results A significant but weak association between urinary Alb or ACR and FF was found in subjects with SK (Spearman correlation coefficients 0.32 and 0.19, respectively). Multivariate analysis also showed that urinary Alb and ACR significantly predict FF only in subjects with a SK (r2 = 0.17, P = 0.01 and r2 = 0.13, P = 0.02, respectively). This holds true only in subjects with a SK and inulin clearance >90 mL/min/1.73 m2 (r2 = 0.41, P < 0.001). There was no association between creatinine clearance and FF. Conclusions MA is not associated with FF in subjects with nephro-urological disorders, except in those with a SK, where the association is weak, indicating that MA is due to other mechanisms than high FF and cannot predict hyperfiltration in such groups.