Low-dose losartan therapy reduces proteinuria in normotensive patients with immunoglobulin A nephropathy

Abstract

The present study was designed to assess the antiproteinuric effects of a low dose of an angiotensin II-receptor blocker, losartan, in normotensive patients with immunoglobulin A (IgA) nephropathy. We performed a prospective, controlled trial of losartan (12.5 mg/d) therapy to assess the effects on mild proteinuria and renal function. The study subjects were 18 normotensive and proteinuric patients with IgA nephropathy in the losartan group and 18 IgA nephropathy patients treated with antiplatelet agents in the control group. We prospectively evaluated blood pressure, proteinuria, renal function, and biochemical parameters before and after 12 months of therapy. Blood pressure was kept constant during the 12-month period. Serum creatinine levels and estimated glomerular filtration rate did not significantly change during the 12 months in any of the patients studied. Systolic and diastolic blood pressures did not differ significantly between the losartan and control groups. However, low-dose losartan significantly reduced proteinuria from 0.8+/-0.5 g/d at baseline to 0.4+/-0.4 g/d at 12 months (p=0.006). Proteinuria was significantly lower at 12 months in the losartan group than in the control group (p=0.04). In addition, urinary N-acetyl-beta-D-glucosaminidase (NAG) levels in the losartan group at 12 months were significantly lower than those in the control group (p=0.009). Our data suggest that low-dose losartan therapy for normotensive patients with IgA nephropathy could reduce the amount of urinary protein and NAG excretion without affecting systemic blood pressure.