Objectives: To compare the efficacy, safety, and tolerance of enalapril and nifedipine in hypertensive patients with non-insulin dependent diabetes.
Design: One year double blind follow up of patients randomly allocated to either enalapril or nifedipine with matching placebos for the alternative drug.
Setting: Metabolic Investigation Unit, Hong Kong.
Subjects: 102 patients were randomised: 52 to nifedipine and 50 to enalapril. At baseline 44 patients had normoalbuminuria, 36 microalbuminuria, and 22 macroalbuminuria.
Main outcome measures: Blood pressure, albuminuria, and parameters of renal function and glycaemic control.
Results: In patients who completed one year's treatment the median dose required by the nifedipine group (n = 49) was 60 mg/day; seven (14%) required additional diuretics. Of 41 patients given enalapril, 37 required the maximum dose (40 mg/day) and 27 (76%) required diuretics. At one year mean arterial blood pressures were similar in both groups. Albuminuria fell by 54% in the enalapril group and 11% in the nifedipine group (p = 0.006). Fractional albumin clearance ratio fell by 47% in the enalapril group and increased by 3% in the nifedipine group (p = 0.009). Creatinine clearance fell similarly in both groups but plasma creatinine concentration was increased by 20% in the enalapril group versus 8% in the nifedipine group (p = 0.001).
Conclusion: Patients taking enalapril often required diuretics to control blood pressure. Enalapril reduced proteinuria significantly more than nifedipine in the microalbuminuric and macroalbuminuric patients but increased plasma creatinine concentrations. Longer follow up is required to clarify the importance of enalapril's antiproteinuric effect.