[The progression of renal damage in reflux nephropathy--clinical analysis of proteinuria in children with vesicoureteral reflux].

To clarify the mechanism for reflux nephropathy to progress to irreversible or marginal renal damages, this study was conducted. We studied 57 cases of VUR in children followed-up more than 3 years after anti-reflux operation and investigated the correlation between changes of urinary protein excretion and clinical data. In general, proteinuria is the most important feature heralding a poor outcome in patients with reflux nephropathy. 9 cases (15.8%) in our series were positive of proteinuria postoperatively. In this positive group, scarring grade had been higher and renal size had been smaller significantly before operation than in other group. From these facts, it would appear that prognosis of refluxing kidney was determined by volume of remnant kidney, and glomerular hyperfiltration of remnant nephron would affect the progression of reflux nephropathy. According to the relationship between changes of urinary protein excretion and scarring grade or renal size, poor prognosis (proteinuria will worsen) would be more than 5 of scarring grade score (cumulation of bilateral scarring grades, Smellie's a = 1, b = 2, c = 3, d = 4) and less than -4S.D. in cumulative renal ratio preoperatively. Then border to progression in reflux nephropathy was between 2 and 4 of scarring grade score, and between -2S.D, and -4S.D. in cumulative renal ratio. In this marginal progression urinary protein excretion and GFR were found to be 100-300 mg/day and 60-75 ml/min, respectively.