Different Patterns of One-year Evolution of Microalbuminuria in Hypertensive Patients Treated with Different Inhibitors of the Renin-angiotensin System

Background: In hypertensive patients (HP) with microalbuminuria (MA) it is not known whether angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) have different renoprotective effects.

Methods: In a prospective open study we studied 71 adult HP (52 with type 2 diabetes) with MA (urinary albumin excretion rate [UAE] 30-299 mg/g creatinine) and estimated glomerular filtration rate (eGFR, MDRD and Cockcroft-Gault methods) > or = 29 ml/min. We evaluated 1-year evolution of UAE, eGFR and blood pressure (BP) in patients undergoing either ARB-based (n=31) or ACEI-based treatment (n=40).

Results: At admission the groups taking ARBs and ACEIs did not differ in age (55 +/- 14 vs. 60 +/- 13 yrs), BP (149/87 +/- 15/14 vs. 155/86 +/- 21/19 mmHg), gender (55 vs. 55% female), percentage with diabetes (81 vs. 68%) or median UAE (59.2 vs. 68.6 mg/g creatinine). At one year BP remained unchanged, eGFR changed by -0.8 +/- 12.0 and -1.8 +/- 10.8 ml/min, and median UAE changed by -13.4 and -8.5 mg/g creatinine, in ARB- and ACEI-based treatments respectively. Regression towards normoalbuminuria (UAE <30 mg/g creatinine) occurred in 11 patients (35.5%) taking ARBs vs. 9 (22.5%) patients taking ACEIs (NS between groups). Progression towards macroalbuminuria (UAE >300 mg/g creatinine) occurred in 1 patient (3%) taking ARBs vs. 8 (20%) patients taking ACEls (p<0.05).

Conclusions: In HP with microalbuminuria, ARBs were superior to ACEIs in reducing 1-year progression to macroalbuminuria despite similar changes in BP, UAE and eGFR and rate of regression to normoalbuminuria.