Renal biopsy criterion in children with asymptomatic constant isolated proteinuria.
BACKGROUND
The criterion of a renal biopsy in children with asymptomatic persistent isolated proteinuria is controversial.


METHODS
To determine an adequate renal biopsy criterion in children with asymptomatic constant isolated proteinuria, the optimal cutoff maximum urinary protein/creatinine ratio (uP/Cr) to separate minor glomerular abnormalities (MGA) and other significant glomerular changes was obtained by receiver operating characteristic analysis in 44 children with asymptomatic constant isolated proteinuria (uP/Cr ≥ 0.2 g/g) screened from 1167 patients who underwent a renal biopsy between September 2000 and April 2010. Patients were divided into two groups according to the cutoff value to verify its validity.


RESULTS
The optimal uP/Cr was 0.5 g/g. In Group 1 (uP/Cr <0.5 g/g, n = 15), only one patient (6.7%) showed focal segmental glomerulosclerosis (FSGS) and the other 14 patients (93.3%) had MGA. In Group 2 (uP/Cr ≥ 0.5 g/g at least once before biopsy, n = 29), 5 patients showed FSGS and 7 patients had nephritis such as IgA nephropathy (41.4%, n = 12) and the other 17 patients (58.6%) showed MGA. These findings indicated that the ratio of non-MGA/MGA was significantly higher in Group 2 than that in Group 1 (P = 0.016) and that if renal biopsies were performed with a criterion of a maximum uP/Cr ≥ 0.5 g/g (criterion for Group 2), renal biopsies could be avoided in 45.2% of patients with MGA. One patient with FSGS in Group 1 showed proteinuria with uP/Cr ≥ 0.5 g/g in the clinical course.


CONCLUSIONS
An adequate renal biopsy criterion in children with asymptomatic constant isolated proteinuria is uP/Cr ≥ 0.5 g/g.
Department of Pediatrics, Wakayama Medical University, Wakayama, Japan.
Taketsugu
T
Hama
Koichi
K
Nakanishi
Yuko
Y
Shima
Hironobu
H
Mukaiyama
Hiroko
H
Togawa
Ryojiro
R
Tanaka
Kiyoshi
K
Hamahira
Hiroshi
H
Kaito
Kazumoto
K
Iijima
Norishige
N
Yoshikawa
D000293:Adolescent; D000581:Amidohydrolases / Q000652:urine; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D005922:Glomerulonephritis, IGA / Q000175:diagnosis / Q000652:urine; D005923:Glomerulosclerosis, Focal Segmental / Q000175:diagnosis / Q000652:urine; D006801:Humans; D007668:Kidney / Q000473:pathology*; D007678:Kidney Glomerulus / Q000473:pathology; D008297:Male; D011507:Proteinuria / Q000473:pathology* / Q000652:urine*
D000581:Amidohydrolases; C019946:creatininase