Evidence of enhanced uric acid clearance in macrohematuric patients with IgA nephropathy: prognostic significance of macrohematuria.

Renal handling of uric acid and clinical prognosis following episodes of macroscopic hematuria (EMH) were examined in 113 patients with IgA nephropathy (IgAN). EMH was observed in 34 out of 113 patients (30.1%). The levels of blood urea nitrogen, proteinuria, serum uric acid, beta 2-microglobulin in sera and the degrees of glomerular sclerosis in renal tissues in macrohematuric patients were significantly decreased than those in patients without EMH. The levels of uric acid clearance (Cua) and fractional excretion of uric acid (FEua) was significantly enhanced in macrohematuric patients (p less than 0.01, p less than 0.05, respectively). There was a significant correlation between the tubular atrophy and the levels of Cua in macrohematuric patients (p less than 0.005). The levels of serum creatinine in macrohematuric patients before and after three years were significantly decreased when compared with microhematuric patients (p less than 0.005). It is concluded that enhanced Cua was related to renal tubular atrophy, and EMH did not clinically influence the glomerular deterioration in patients with IgAN.