Morphometric aspects of reflux nephropathy.

We have studied the relationships between renal size, glomerular hypertrophy and sclerosis and renal function in adults with reflux nephropathy. A digitizer was used to measure the renal surface areas in intravenous pyelogram films. This was then corrected for patient size by dividing by the area of the first three lumbar vertebrae. In renal biopsies, glomerular surface area and the proportion of segmentally and globally sclerosed glomeruli were measured and compared with a control group of 17 renal donors. Of 57 patients studied, 45 had intravenous pyelogram films and 32 had renal biopsy tissue available from the time of presentation, 20 had both. Thirty-one were followed for two years or more (median 6 years, range 2 to 11 years). There were positive correlations between corrected renal size and renal function, and inverse correlations between these and maximum glomerular size, the proportion of sclerosed glomeruli and vascular wall thickness. Proteinuria correlated best with the proportion of segmentally sclerosed glomeruli. As a prognostic guide, the strongest correlations were between rate of functional decline and percent segmental sclerosis, urine protein excretion and creatinine clearance at presentation. These studies confirm expected relationships between renal size, glomerular size and renal function and suggest that the severity of segmental sclerosis is a major factor in eventual decline into renal failure.