Drugs Show Promise in Treating Complications of Diabetes
A popular family of blood pressure drugs can delay and possibly even prevent the progression of kidney disease in diabetics, reducing the need for dialysis and transplants by thousands each year, three research groups report today.
The drugs are called angiotensin II receptor blockers, and their kidney-sparing properties seem to be over and above their ability to lower blood pressure.
Some researchers already are saying that all diabetics with early evidence of kidney disease--about half of the 16 million Type 2 diabetics in the United States--should be taking the drugs. Because 30% of diabetics develop severe kidney failure, also called end-stage renal disease, doctors eventually might recommend that all diabetics take them.
“This will have a major impact,” said Dr. Scott Campbell, research director for the American Diabetes Assn. “Anything that delays the onset of end-stage renal disease is beneficial. This will mean better quality of life, less hospitalization and less expense.”
About 300,000 Americans now must undergo kidney dialysis because of end-stage renal failure, about 40% of those as a result of diabetes. Another 80,000 are living with transplanted kidneys, with about 13,000 new transplants annually.
Dr. Barry M. Brenner of Brigham and Women’s Hospital in Boston, author of one of the studies, noted that kidney failure is now increasing by 2% per year in the United States. But widespread use of the drugs could reverse that trend, he said.
“That’s why I’m so excited by these findings,” Brenner said. “This will make a major dent in this pandemic . . . Doctors will quickly adopt this.”
The drugs studied in the three articles in today’s New England Journal of Medicine were losartan (trade named Cozaar) and irbesartan (trade named Avapro). They work by relaxing blood vessel walls. Other members of the family that were not studied include Diovan, Atacand, Teveten and Micardis. But because they operate in a similar manner as Cozaar and Avapro, researchers believe they will produce similar benefits on kidney disease.
Brenner’s study enrolled 1,513 patients with diabetes, high blood pressure and early signs of kidney disease. All were given conventional treatment for their diabetes and blood pressure. Half also were given losartan and half a placebo.
The patients were followed for an average of 3.4 years. At the end of the study, the incidence of end-stage renal failure was 28% lower in the group receiving losartan.
Brenner estimated that, during the three years of the study, the drugs could have prevented 38,000 cases of kidney failure in the United States if all diabetics with kidney damage had taken them. The financial savings, he estimated, would have been $1 billion annually, even after the cost of the drugs was included.
In a second study, a team headed by Dr. Edmund J. Lewis of Rush-Presbyterian-St. Luke’s Medical Center in Chicago followed 1,715 diabetics with kidney disease. In addition to conventional treatment, they were given either irbesartan, another blood pressure drug called amlodipine (Norvasc) or a placebo.
Their study averaged 2.6 years of follow-up, and they concluded that patients receiving irbesartan were 20% less likely to have end-stage renal failure than patients receiving placebo and 23% less likely than those receiving amlodipine.
A smaller study from the Steno Diabetes Center in Copenhagen found similar results with irbesartan.
None of the studies, however, found a reduced death rate associated with use of the drugs.
Despite the promise of these drugs, researchers noted that diabetes is a highly preventable disease. Recent studies have shown that a combination of a low-calorie diet and modest exercise can reduce the incidence by more than half, eliminating the risk of kidney failure.
