Treatment with ACE inhibitors can delay kidney damage
Treatment with ACE inhibitors can delay kidney damage
April 11 1996
By: Thomas Pickering, MD, DPhil, FRCP, Director of Integrative and Behavioral Cardiology Program of the Cardiovascular Institute at Mount Sinai School of Medicine, New York
New England Journal of Medicine Vol. 334, page 939
Kidney damage can occur from a number of causes, many of which are initially unrelated to high blood pressure; examples are diabetes and glomerulonephritis (an inflammatory process affecting the kidneys). Not only do the kidneys fail to remove the waste products from the blood, but they also tend to leak protein into the urine. Once a certain degree of kidney damage occurs, however, the blood pressure starts to rise and a relentless process begins whereby the kidney damage progresses, until the patient needs to go on dialysis. There is increasing evidence that aggressive control of the blood pressure may delay the rate of deterioration, and it has also been proposed that angiotensin converting enzyme (ACE) inhibitors may be particularly beneficial.
A three-year study conducted in Italy recruited 583 patients with a variety of kidney diseases, half of whom had benazepril (an ACE inhibitor, marketed in the US as lotensin) added to their treatment, and half had placebo (inert pills) added. At the end of three years, the rate of decline of kidney function was about 50% lower in the patients taking benazepril than in those treated with placebo. The blood pressure was also significantly lower in the benazepril group. Patients whose kidney disease was from diabetes, and those who had a large amount of protein in their urine at the start of the study showed the greatest benefit.
Doctor's Comments
This study implies that ACE inhibitors should be more widely used in the treatment of patients with progressive kidney failure. Many physicians have been reluctant to use ACE inhibitors in these patients, because in a small minority, particularly patients whose kidney damage is caused by blockage of the renal arteries, ACE inhibitors can make the renal function worse, as manifested by a rise in the blood level of creatinine (one of the waste products excreted by the kidneys). One of the interesting findings in this study is that the benazepril group did show an initial increase in their creatinine levels, but after two months, the placebo group increased their creatinines even more.
It is not clear from this study whether the benefits from the ACE inhibitor were the result of the lower blood pressure or from some other effect (other studies are now attempting to answer this question). In patients with insulin-dependent diabetes, who are particularly susceptible to kidney damage, there is other evidence to suggest that there is a beneficial effect of ACE inhibitors, which is not just from blood pressure reduction, because other drugs which lower blood pressure by the same amount do not help the kidneys as much. Although this study used benazepril, it is probable that the same benefits would be obtained with other drugs of this class.
Where it was published
Maschio G and colleagues. Effect of the angiotensin-converting-enzyme inhibitor benazepril on the progression of chronic renal insufficiency. New England Journal of Medicine Vol. 334, page 939, April 11 1996
