Background: The aim of this study is to compare the long-term effect of amlodipine and fosinopril in monotherapy or in combination on urinary albumin excretion (UAE) in hypertensive diabetic patients.
Methods: We selected 453 hypertensive patients with type 2 diabetes and microalbuminuria and randomized them to amlodipine (5 to 15 mg/day), fosinopril (10 to 30 mg/day), or amlodipine plus fosinopril (5/10 to 15/30 mg/day) for a 3-month titration period. The nonresponder patients or those complaining of side effects during the titration period were discontinued (n = 144); the remaining 309 patients were enrolled in the trial and treated with the same therapy for 4 years. Every 6 months, blood pressure (BP), heart rate (HR), UAE, creatinine clearance, and glycosylated hemoglobin (HbA1c) were evaluated.
Results: The combination therapy was more effective in reducing BP than either drug alone at any time of the study without affecting glucose homeostasis. All three treatments provided a significant decrease in UAE during the 48-month study period. However, this effect was more pronounced and became evident earlier with fosinopril than with amlodipine monotherapy (after 3 v 18 months of therapy). In addition, the combination therapy provided a greater antialbuminuric effect than the single drugs. This could be due to the greater antihypertensive effects, although other drug-specific effects cannot be excluded. The cardiovascular outcomes were similar in the amlodipine and in the fosinopril group, but they were lower in the combination group.
Conclusions: These results strengthen the rationale to use a calcium-antagonist/angiotensin converting enzyme inhibitor combination in the treatment of hypertensive patients with type 2 diabetes.