THURSDAY, June 9, 2011 (HealthDay News) -- The cholesterol-lowering drug Vytorin reduced the risk of heart disease among kidney patients by as much as 25 percent, according to the results of the largest kidney disease trial ever conducted.
"People with kidney disease are at a high risk of heart attack and strokes," explained study author Dr. Colin Baigent, a professor of epidemiology at the University of Oxford in the U.K. "But there are very few studies attempting to see how that risk can be reduced. In healthy people we know that lowering LDL, or 'bad,' cholesterol reduces the risk. But now this is the first study to show that lowering LDL among people with kidney disease reduces risk as well."
Baigent and his colleagues report on their research, which was funded in part by Vytorin maker Merck/Schering-Plough Pharmaceuticals, in the June 9 online issue of The Lancet. The findings were to be presented this week at the UK Renal Association and British Renal Society meeting being held this week in Birmingham, England.
Vytorin is a combination of Zetia (ezetimibe) and the statin Zocor (simvastatin). Yesterday, the U.S. Food and Drug Administration called for warning labels on Zocor because of an increased risk of muscle damage that is seen among patients taking the highest dose -- 80 milligrams a day -- of that drug.
Baigent noted that although statins alone are known to be effective at lowering LDL, one of the challenges of treating kidney disease patients is that they do not process such drugs well, rendering high doses of statins potentially toxic. However, by pairing a relatively low dose of the statin Zocor with Zetia, the team hoped to achieve the same LDL-lowering effect while using a much lower dose of a statin.
"This is a rather neat trick," said Baigent, who struggled with kidney disease himself some three decades ago. "This combination produces the same LDL-lowering effect as would triple the dose of statin alone."
In this study, the authors focused on a pool of nearly 9,300 male and female chronic kidney disease patients aged 40 and up (with an average age of 62). All were participants in the "Study of Heart and Renal Protection" (SHARP) study, which was conducted over a seven-year period at 380 hospitals spread across 18 countries.
Beginning in 2003, roughly one-third of the patients were already on dialysis at the study's launch. Nearly two-thirds were men, and none had a prior history of heart attack.
About half of the patients were randomly given Vytorin; the other half was given placebo pills.
Patients were tracked for a minimum of four years. The team recorded all instances of heart attack, stroke, vascular procedures, hospitalizations and side effects.
The results: The Vytorin group experienced 17 percent fewer major cardiovascular events, compared with the placebo group.
What's more, because about a third of the Vytorin group failed to take the drug all the time, the researchers calculated that, with 100 percent compliance, Vytorin would actually have lowered the risk for major cardiovascular events by roughly 25 percent.
"This finding has major implications, both for people who are on kidney dialysis, and also the larger group of people who have some stage of kidney disease but have not yet reached the stage where they need dialysis," Baigent said.
"So, this will have ramifications for many, many millions of people," he added, "given the estimated 10 percent of the population that has some form of kidney disease."
Dr. Robert Provenzano, chief of nephrology at St. John Hospital and Medical Center in Detroit, echoed Baigent's opinion.
"Chronic kidney disease is an epidemic in the world," he said. "As other countries become 'Westernized,' we find the incidence of chronic kidney disease and end-stage renal failure increases. We see this in India, and in China. We see this everywhere. So, this is a huge issue."
"The problem though is that even though we've already identified the basic risk factors, so far most of the data concerning cholesterol and risk has been circumstantial or confounded by a lot of other problems," Provenzano noted. "But now the SHARP study has answered the question, and found that LDL, bad cholesterol, directly impacts acceleration of chronic kidney disease. And they've found a way to get around the high side-effect profile of statins by combining them with another medication."
"Now if you have kidney disease, this won't cure you per se," he cautioned. "But it treats the co-morbidities that can kill these patients. And that makes this finding extremely useful."
For more on kidney disease and heart disease risk, visit the National Kidney Foundation.