ACE inhibition reduces proteinuria in normotensive patients with IgA nephropathy: a multicentre, randomized, placebo-controlled study

A multicentre, randomized, placebo-controlled study was performed in 39 adult patients with biopsy-proven IgA nephropathy with the aim of comparing the effects of the ACE inhibitor fosinopril and placebo on proteinuria. All patients had normal blood pressure and normal renal function. Proteinuria ranged from 1.0 to 2.5 g/24 h. After a 3-month run-in period, fosinopril and placebo were randomly administered in two 4-month sequences separated from cross-over treatment by a 1-month interval. The mean values of creatinine clearance did not change during either the placebo or the treatment sequences. The mean values of mean arterial pressure (MAP) were significantly lower during the fosinopril sequence (90.4 +/- 9.0 mmHg) than in basal conditions (92.8 +/- 9.1 mmHg) (P = 0.034). The mean basal values of proteinuria were 1.74 +/- 0.84 g/24 h. They were unchanged during the placebo sequence (1.79 +/- 1.20) and fell to 1.37 +/- 0.98 g/24 h after 4 months of fosinopril treatment. Using a multivariate statistical analysis, the treatment effect by time on proteinuria was significantly evident only in the fosinopril sequence (Wilks test, P = 0.033). Changes in protein excretion were not correlated with changes in MAP, baseline plasma renin activity, and urinary sodium excretion. This controlled study shows that fosinopril can significantly reduce proteinuria even in normotensive patients with IgA nephropathy. Obviously, the results of treatment with ACE inhibitors on long-term renal prognosis remain to be elucidated.