Proteinuria in children after renal transplantation.

Proteinuria is associated with poor long-term allograft as well as patient survival among adults after renal transplantation. In children, there are no studies focusing primarily on posttransplant proteinuria. The aim of this cross-sectional study was to investigate the prevalence of and possible risk factors associated with proteinuria. Thirty-three children (mean age of 13.7 +/- 4.3 years; mean time after renal transplantation = 2.3 +/- 2.2 years) were eligible for the study. There was an 82% prevalence of proteinuria (> or =96 mg/m2/d) with nephrotic range proteinuria (> or =960 mg/m2/d) in 12% of children. The mean urinary protein excretion was 256 +/- 299 mg/m2/d (range = 47 to 1264). Children with hypertension, as defined by ambulatory blood pressure monitoring, showed significantly higher proteinuria than normotensive children (382 +/- 435 vs 163 +/- 79 mg/m2/d, P < .05). Children with a history of a previous acute rejection episode showed significantly higher proteinuria than children who never had an episode (416 +/- 445 vs 165 +/- 91 mg/m2/d, P < .05). Children with proteinuria did not show statistically different graft function than children without proteinuria. No statistically significant correlation was observed between proteinuria and ambulatory blood pressure values or graft function. In conclusion, proteinuria is a frequent finding also in children after renal transplantation; it is associated with hypertension and a history of rejection episodes.