Blood Pressure Drug Delays Kidney Disease in Diabetics
WEDNESDAY, March 9 -- A drug normally used to lower blood pressure may also help protect the kidneys of people with type 2 diabetes, researchers are reporting with a caveat.
In a new study, an international team of researchers found that the drug pressure-reducing medication olmesartan, brand name Benicar, could increase the time before any kidney problems were evident by 23 percent.
The study measured the possibility of kidney function problems by measuring the amount of albumin secreted in the urine (microalbuminuria).
"Olmesartan was associated with a delayed onset of microalbuminuria, even though blood-pressure control in both groups was excellent according to current standards," wrote the study's authors in a report published in the March 10 issue of the New England Journal of Medicine,
"Microalbuminuria is a marker for renal disease, and preventing renal disease is important for longevity," said Dr. Julie Ingelfinger, the deputy editor of the journal and author of an accompanying journal editorial. She added, "It is possible to use medications preemptively to delay or prevent the onset of microalbuminuria."
But news from the study wasn't all good. More patients in the olmesartan treatment group had fatal cardiovascular events compared to those in the placebo group. Fifteen people with preexisting heart conditions who were taking the drug died from heart problems versus three people taking the placebo.
Ingelfinger said that it's impossible to know right now if this was a chance finding, or if somehow the drug might have contributed to these deaths. She said the U.S. Food and Drug Administration was still investigating the deaths. On its Website, the FDA said that at this point it still feels the benefits of the drug outweigh the potential risks for people with high blood pressure.
Olmesartan is part of a class of medications known as angiotensin II receptor blockers, or ARBs, which are medications that help relax blood vessels and lower blood pressure.
In her editorial, Ingelfinger also pointed out that olmesartan was approved by the FDA in 2002 for treating high blood pressure, so it's likely that if the drug were responsible for an increased cardiovascular risk, such a risk would be evident by now.
The latest research came from a randomized, double-blind controlled trial called Roadmap, which was sponsored by the drug's maker, Daiichi Sankyo. It included 4,447 people with type 2 diabetes at 262 centers in 19 European countries. The study volunteers were between the ages of 18 and 75, with an average age of 58 years. Forty six percent were male. Just under 25 percent had a history of heart disease. On average, the volunteers had been diagnosed with type 2 diabetes for six years, and had slightly elevated systolic (the top number) blood pressure levels.
Half the group was randomly assigned to receive 40 milligrams of olmesartan once a day, or a daily placebo pill for an average of 3.2 years.
Target blood pressure levels (less than 130/80 mm Hg) were achieved in nearly 80 percent of those on olmesartan, and 71 percent of those on placebo. Microalbuminuria developed in 8.2 percent of those on olmesartan and 9.8 percent in the placebo group.
The time to onset of microalbuminuria was extended for people taking olmesartan by 23 percent compared to those on placebo.
Nonfatal heart problems occurred in 81 of the people taking olmesartan versus 91 of those on placebo. However, fatal cardiovascular events were more common in people taking olmesartan compared to those on placebo: 15 to 3.
"The small number of events in a large study can be a statistical fluke," explained Dr. Joel Zonszein, director of the clinical diabetes center at the Montefiore Medical Center in New York City. Or, he said, in providing medication to those who already had existing heart disease, it could be a case of "too much, too late," and that "lowering blood pressure too much in ill patients may not be beneficial."
Still, he said, it appears that the benefits of the drug likely outweigh the potential risk. The number of fatal events in this study was so small that it's too soon to jump to any conclusions, he noted.
"ARBs are good medications, especially in diabetes," said Zonszein, who pointed out that in previous research, ARBs were even shown to prevent the onset of type 2 diabetes.
To learn more about kidney disease and type 2 diabetes, visit the American Diabetes Association.
Posted: March 2011