Potential role of urinary angiotensinogen in predicting antiproteinuric effects of angiotensin receptor blocker in non-diabetic chronic kidney disease patients: a preliminary report.

Abstract

Many chronic kidney disease (CKD) patients have persistent overt proteinuria despite angiotensin receptor blocker (ARB) treatment. This study investigated whether the initial difference in intrarenal renin-angiotensin system activity measured with urinary angiotensinogen would affect the antiproteinuric effects of ARB. Between September 2005 and September 2008, in 50 non-diabetic proteinuric CKD patients not taking renin-angiotensin system inhibitors, the urinary protein/creatinine ratio (P/Cr), angiotensinogen/creatinine ratio (AGT/Cr), plasma renin and aldosterone were measured before starting valsartan, and were followed for 18 months. Patients were divided into three groups according to their initial urinary AGT/Cr. The urinary P/Cr was lower in the low angiotensinogen group, but similar in the high and extremely high angiotensinogen groups (1.3±0.38 vs 2.0±0.92 vs 2.2±0.78). In all groups, the urinary P/Cr was decreased most for the first 6 months. The urinary P/Cr reduction at 6 months was greatest in the high angiotensinogen group (-24.2% vs -46.2% vs -16.4%). The urinary AGT/Cr was decreased most in the high angiotensinogen group. Renal functional deterioration was attenuated in the high angiotensinogen group compared with the extremely high angiotensinogen group. The antiproteinuric effects of ARB were different according to the initial urinary angiotensinogen levels. These results suggest the potential value of the initial urinary AGT/Cr for predicting the therapeutic effect of ARB in proteinuric non-diabetic CKD patients.