Clinical Question: Are angiotensin-converting enzyme (ACE) inhibitors or angiotensin-II receptor blockers (ARBs) beneficial in patients with diabetes who have microalbuminuria or macroalbuminuria?
Setting: Outpatient (any)
Study Design: Meta-analysis (randomized controlled trials)
Synopsis: Investigators searched several data-bases using Cochrane Collaboration search strategies. Study selection, data extraction, and quality assessment were performed in the usual manner. They used 43 randomized studies enrolling 7,545 patients. Most of the research compared an ACE inhibitor with placebo in diabetic patients with microalbuminuria and pre-existing heart disease (the MICRO-HOPE study). Treatment with an ACE inhibitor decreased overall mortality (8.50 versus 12.12 percent). The number needed to treat was 44 for approximately 4.5 years, although the range was large (95 percent confidence interval, 24 to 938). ARBs, which were studied in similar numbers of patients but for shorter time periods, have not shown any effect on mortality.
ACE inhibitors did not decrease the development of end-stage renal disease, although the rate was low to begin with (4.3 percent) in the patients who were studied. ARBs have had an effect in patients at high risk (19.3 percent) of developing end-stage renal disease. Similarly, ARBs, but not ACE inhibitors, have had an effect on progression of renal disease as measured by the doubling of serum creatinine levels.
Both types of drugs decreased the number of patients with microalbuminuria who progressed to macroalbuminuria, although the significance of this outcome is not known. There is not enough research directly comparing the two types of drugs to determine which is better.
Bottom Line: Treatment with ACE inhibitors, but not with ARBs, delays mortality in patients with diabetes who also have microalbuminuria (and pre-existing heart disease) or frank albuminuria. This benefit occurs regardless of whether patients also were hypertensive. ARBs have been shown to prevent a decline in renal function and decrease the likelihood of end-stage renal disease in high-risk patients. This analysis does not provide good evidence that screening for and treating microalbuminuria are effective in patients with diabetes but without heart disease. (Level of Evidence: 1a)