Effects of Olmesartan and Azilsartan on Albuminuria and the Intrarenal Renin-Angiotensin System

Purpose: Olmesartan and azilsartan decrease blood pressure more effectively than other angiotensin receptor blockers (ARBs). ARBs additionally decrease the urinary albumin to creatinine ratio (UACR), a urinary albumin marker, and urinary angiotensinogen (u-AGT), an intrarenal renin-angiotensin system activity marker. We examined the effects of these ARBs on blood pressure, UACR, and u-AGT in patients with uncontrolled hypertension. Methods: Patients with uncontrolled hypertension treated with conventional ARBs, excluding olmesartan and azilsartan, for over 8 weeks were enrolled. We randomly switched patients from their prior ARBs to either olmesartan or azilsartan, and followed them for 24 weeks. Results: Systolic blood pressure (SBP), diastolic blood pressure (DBP), and central systolic blood pressure (cSBP) significantly decreased at 24 weeks. UACR and u-AGT also decreased at 24 weeks in both groups. There were no significant differences in SBP, DBP, cSBP, UACR, or u-AGT between the groups. Therefore, we combined both groups for further analyses. After combining, SBP (160.5 plusmn 16.4 to 139.6 plusmn 15.6 mm Hg, P lt 0.0001), DBP (88.4 plusmn 13.7 to 80.7 plusmn 13.2 mm Hg, P = 0.008), cSBP (167.4 plusmn 20.8 to 146.6 plusmn 24.6 mm Hg, P lt 0.0001), UACR (13.8 to 9.0 mg/g Cre, P = 0.0096), and u-AGT (4.13 to 2.32 microg/g Cre, P = 0.0074) significantly decreased at 24 weeks. Patients with microalbuminuria (UACR ge 30 mg/g Cre) had significantly greater DeltaUACR (-39.4 vs 0.27, P = 0.0024) and Deltau-AGT (-11.9 vs -0.61, P = 0.0235) than patients without microalbuminuria. The changes in u-AGT were significantly associated with changes in UACR (r = 0.411, P = 0.046) however, there was no significant relationship between the changes in u-AGT and those in SBP or DBP. Conclusion: Olmesartan and azilsartan decreased blood pressure, UACR, and u-AGT more than the other ARBs, and exerted depressor and renoprotective effects.