BOSTON (AP) _ A type of drug already widely used to lower blood pressure can substantially delay and perhaps prevent kidney failure in diabetics, a discovery that could eliminate tens of thousands of new dialysis and transplant cases each year.
Doctors found that the medicines, called angiotensin II receptor blockers, forestall complete kidney failure by about two years in diabetics with advanced kidney disease. They predict the effects will be even more dramatic in those with less severe kidney damage, potentially protecting them from ever reaching end-stage disease.
Dr. Barry M. Brenner of Boston's Brigham and Women's Hospital calculated that during the three years of his study, the drugs could have prevented 38,000 cases of kidney failure in the United States alone if all diabetics with kidney damage had taken them. The financial saving, even after the cost of the medicine, would approach $1 billion annually.
Brenner noted that kidney failure is increasing by 2 percent a year in the United States. ``If we can begin to impact that in new diabetics, they may never get there,'' he said. ``That's why I'm so excited by these findings. This will make a major dent in this pandemic.''
Brenner's study and two others involving a total of 3,818 patients were published in Thursday's issue of the New England Journal of Medicine. The studies showed the effects of two angiotensin blockers, Bristol-Myers Squibb's Avapro and Merck's Cozaar. They were initiated by academic researchers and financed by the manufacturers.
Other brands of the drugs include Atacand, Diovan, Micardis and Teveten. Researchers say they believe all of them probably have similar effects.
``This will have a major impact,'' predicted Scott Campbell, the American Diabetes Association's research director. ``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 are on kidney dialysis because of organ failure, and 80,000 more are living with transplanted kidneys. Diabetes is the underlying cause of about 40 percent of all kidney failure.
Authors of the new studies recommend that angiotensin blockers be taken by all diabetics who show signs of kidney damage. This amounts to nearly half of the 16 million diabetics in the United States. The damage is diagnosed by tests that look for abnormal levels of proteins in the urine.
Dr. Gerald Bernstein of Beth Israel Medical Center in New York City said the next question is whether all diabetics should be on these drugs, regardless of whether they have kidney damage. ``If the data keep getting stronger, it will become a recommendation, because there is very little downside to these drugs,'' he said.
Diabetes has reached epidemic levels in the United States and around the world, fueled by obesity and the aging of the population. The Centers for Disease Control and Prevention estimates the disease increased by one-third during the 1990s.
Angiotensin blockers work by relaxing the blood vessels. They are particularly helpful because they lower dangerous pressure in the delicate capillaries in the kidney that are responsible for forming urine.
An older class of blood pressure drugs, called ACE inhibitors, may do the same thing. This has already been shown in people with type 1 diabetes, which usually strikes in childhood or adolescence. However, this has not been convincingly proven in people with the dominant form of diabetes, called adult-onset or type 2 diabetes, which accounts for about 95 percent of all cases.
The latest studies were conducted on people with type 2 diabetes. Dr. Edmund J. Lewis of Rush-Presbyterian-St. Luke's Medical Center in Chicago, who directed one of them, said drug companies were not interested in testing the benefits of ACE inhibitors in these patients, since the patents on these drugs are expiring.
Angiotensin blockers have fewer side effects than ACE inhibitors, which cause a cough in about 20 percent of users.