Comparative study of the effect of ACE-inhibitors and other antihypertensive agents on proteinuria in diabetic patients.

Several studies during the past 15 years have shown that antihypertensive therapy with different types of drugs can reduce microalbuminuria or clinical proteinuria and retard the progression toward end-stage renal failure. However, some authors reported disparate renal protective effects of different antihypertensive drugs in diabetic animals and humans. In an attempt to resolve the controversy surrounding this possibility, previously we reported a meta-analysis of published studies in diabetics with microalbuminuria or overt proteinuria treated with conventional agents, angiotensin-converting enzyme (ACE) inhibitors, or calcium antagonists (Ca2+ antagonists). Here we present an updated meta-analysis of published studies in diabetics with microalbuminuria or clinical proteinuria (UProt), treated during > or = 4 weeks with ACE inhibitors, Ca2+ antagonists, or conventional therapy (diuretic and/or beta-blocker). Despite similar blood pressure (BP) reductions, UProt tended to decrease more on ACE inhibitors (on average -45%) than on conventional therapy (on average -23%) or Ca2+ antagonists other than nifedipine (on average -35%); in contrast, UProt tended to increase slightly on nifedipine (on average 5%, P < .05). On the basis of multiple regression analysis, ACE inhibitor-induced UProt changes correlated with BP changes (r = 0.77, P < .00001), averaged -28% at zero BP change, and varied 1.5% for each percent BP change. On conventional therapy, UProt and BP changes also correlated (r = 0.62, P < .005), but UProt began to decrease only after a BP reduction of > 5% and the slope was steeper (4% UProt change per percent BP change) than on ACE inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)