Thirty-nine hypertensive patients with
type 2 diabetes mellitus were followed under long-term treatment (mean, 20.7 months) with
manidipine hydrochloride, a Ca antagonist, or
delapril hydrochloride, an
ACE inhibitor, at nine institutions. Both the treatments showed similar
antihypertensive effects, although slight but significantly larger decreases were observed in systolic and mean blood pressures at months 12 and 24 in the patients treated with
manidipine (P < 0.02). The urinary
albumin excretion index (AEI) tended to increase throughout the study in both treatment groups, but no significant difference in AEI was observed between the two treatment groups at any time point. Overt
albuminuria developed in four patients on
manidipine but did not appear in any of the patients on
delapril. The risk of progression to overt
albuminuria was significantly different between
manidipine and
delapril groups (P = 0.011). No increase in serum
creatinine (Cr) was observed with
delapril. The average excretion indexes of tubular markers such as beta2-microglobulin, alpha1-microglobulin, and NAG tended to be higher in the patients on
manidipine than in those on
delapril. Taken in sum, these findings suggest that the
ACE inhibitor delapril is more beneficial than the Ca antagonist
manidipine in the treatment of diabetic renal diseases via mechanisms other than the blood pressure regulation, partly through their different effects on tubular function. In conclusion,
delapril was significantly more effective than
manidipine in inhibiting progression to overt
albuminuria in hypertensive
type 2 diabetes mellitus patients.