We investigated chronic renal failure (CRF) in 166 Iranian children (95 boys and 71 girls) from July 1991 to June 1999. The mean age at onset of CRF was 7.9+/-4.5 years. The most common cause of CRF was congenital urological malformations (78 cases). The second most common cause of CRF was hereditary nephropathy (21%). Glomerular diseases accounted for only 10% of children who later went on to develop renal failure. High rates of cystinosis and primary hyperoxaluria were seen, and these elevated rates could be due to a high prevalence of parental consanguinity. Eighty-six patients required renal replacement therapy, of whom the majority underwent hemodialysis. The prevalence of primary reflux as a cause of CRF was high compared with reports from western countries. Earlier diagnosis and management of urinary tract infections in this group could reduce the prevalence of reflux as a cause of CRF in this population.

Based on our findings, the survival rate of the kidney is significantly lower in children with prior cystoplasty, possibly due to the higher prevalence of chronic rejection and febrile urinary tract infection in this group.

Initial serum creatinine is a valuable factor for prediction of renal outcome in patients with PUV.

BACKGROUNDSpot urine is recommended as an accurate method to determine proteinuria in children and adults. However, urinary excretion of creatinine may vary in newborns and spot urine may be influenced by the hydration-dehydration condition of patients. The study was done to assess the validity of the urine protein to osmolality ratio versus the urine protein to creatinine ratio in health and disease conditions.METHODSWe studied the correlation of the urine protein-osmolality ratio (Uprot/Uosm) and the urine protein to creatinine ratio (Up/Ucr) and compared results with the 24-hour urinary protein excretion. Three groups were compared: children with normal renal function and without proteinuria (group 1, n=53), children with normal renal function and with proteinuria (group 2, n=52) and patients with renal insufficiency (group 3, n=45). Early morning urine samples and 24-hour urine specimens were collected for protein, creatinine, and osmolality.RESULTSThe optimal cutoff value of the Uprot/Uosm ratio was determined to be 0.33 mg/L/mosm/kgH2O for abnormal proteinuria and 1.75 mg/L/mosm/kgH2O for nephrotic range proteinuria. In comparing ROC curves, we found no differences between the Uprot/Uosm and Up/Ucr ratios in detecting abnormal proteinuria or nephrotic syndrome in children with normal or decreased renal function (P>0.05).CONCLUSIONBoth the Uprot/Uosm and Up/Ucr ratios from random urine specimens are good predictors of 24-hour urinary total protein excretion in children with and without renal insufficiency.