Effect of imidapril versus ramipril on urinary albumin excretion in hypertensive patients with type 2 diabetes and microalbuminuria

Objective: Aim of this study was to compare the antiproteinuric effect of imidapril (I) and ramipril (R) in diabetic hypertensive patients with microalbuminuria. Research design and methods: One hundred and seventy-six patients were randomised to I 10-20 mg once daily (od) (n = 88) or R 5-10 mg od (n = 88) for 24 weeks. Clinic, ambulatory, central blood pressure (BP), urinary albumin excretion (UAE), plasma Angiotensin II (Ang II), bradykinin and brain natriuretic peptide (BNP) were assessed at baseline and after 6, 12 and 24 weeks. Results: Both I and R produced a similar decrease in clinic, ambulatory and central BP (p < 0.001 vs baseline). Both treatments significantly reduced UAE throughout the study, but the decrease in UAE associated with I was more pronounced, being evident at week 6 (p = 0.05) and maximal at week 24 end-point (-42 vs -29%, p < 0.01). BNP and Ang II levels were similarly reduced by I and R, while bradykinin increased more with R (+132 vs +86%, p < 0.05). Conclusions: These findings showed that in diabetic hypertensive patients with microalbuminuria, despite equivalent BP-lowering effect, I produced a greater antiproteinuric effect than R, which might be due to different intrinsic molecular properties of the two drugs.