Absence of hypoalbuminemia despite massive proteinuria in focal segmental glomerulosclerosis secondary to hyperfiltration

We observed that some patients do not develop hypoalbuminemia despite the presence of massive proteinuria. To investigate whether the absence or presence of hypoalbuminemia could be a marker in the distinction between idiopathic focal segmental glomerulosclerosis (FSG) and FSG secondary to hyperfiltration, we reviewed all our patients with biopsy-proven FSG and persistent nephrotic-range proteinuria (>3.5 g/24 h). Patients who met these conditions were then separated into those with hypoalbuminemia (serum albumin level <3 g/dL; group I; n = 19) and those with normoalbuminemia (>3.5 g/24 h; group II; n = 18). All group I patients had nephrotic edema in contrast with the absence of edema in all group II patients. Serum cholesterol and triglyceride levels were significantly greater in group I. All group I patients had been diagnosed with idiopathic FSG. The diagnoses of group II patients were FSG secondary to massive obesity in eight patients (44%), vesicoureteral reflux in five patients (27%), and renal mass reduction in three patients (16%); only two patients (11%) in this group had idiopathic FSG. The case histories of 19 other patients with nephrotic-range proteinuria associated with hyperfiltering disorders (reflux nephropathy, massive obesity, renal mass reduction), but without renal biopsy, were also reviewed; despite massive proteinuria (5.8 +/- 3.1 g/24 h), serum albumin and total protein levels were always within normal values. In conclusion, patients with FSG secondary to hyperfiltration do not develop hypoalbuminemia or the other characteristic complications of nephrotic syndrome, despite the presence of massive proteinuria values.