Optimal urinary protein-to-creatinine ratio as a renal biopsy criterion in children with asymptomatic proteinuria.

Abstract

This retrospective case series aimed at exploring the optimal urinary protein-to-creatinine ratio (uP/uCr) cut-off value to determine the need for renal biopsy in pediatric patients with isolated asymptomatic proteinuria (ASP). Data from 32 patients (16 boys, 16 girls) with persistent isolated ASP treated between January 2001 and September 2010 were analyzed. The uP/uCr cut-off value at which a renal biopsy is indicated was determined using the minimum p-value approach. An "optimal" cut-off value was selected to distinguish significant and non-significant glomerular changes. The minimum p-value approach using the χ2-test resulted in a peak uP/uCr of 0.5 g/g x Cr, which was then used to divide the patients into a low-proteinuria group and a high-proteinuria group. The proportion of significant glomerular changes was marginally higher (p = 0.097) in the high-proteinuria group than in the low-proteinuria group after adjustment for multiple tests. In addition, the number of patients with severe proteinuria at the most recent followup was higher in the high-proteinuria group than in the low-proteinuria group. The use of a uP/uCr >= 0.5 g/g x Cr may be a reasonable criterion for renal biopsy aimed at distinguishing renal outcomes in patients with persistent isolated ASP.