HONG KONG, Feb 26 (Reuters) - Lowering the blood pressure of kidney patients who are on dialysis appears to reduce their risk of death from cardiovascular disease, researchers in Australia have found.

Worldwide, more than a million people receive regular dialysis and up to 20 percent of them die each year, with 45 percent of these deaths attributed to cardiovascular causes.

Due to reduced kidney function, many renal patients tend to have high blood pressure, which has long been linked to cardiovascular problems such as heart attack and stroke.

But doctors are often reluctant to lower their blood pressure because they do not know if that would open up patients to unknown risks.

In an article published in the medical journal The Lancet, doctors in Australia said they analysed data from eight previous trials where a total of 1,679 dialysis patients had their blood pressure put under control.

Fewer of them subsequently suffered heart attack or stroke compared to control groups, or other dialysis patients whose high blood pressure was left untreated.

"The benefits of lower blood pressure are very large. What we are talking about is giving them regular blood pressure lowering agents. Their blood pressure will be lowered and their risk of cardiovascular disease and death would be much, much less," said Vlado Perkovic at the George Institute in Sydney.

"Risk of cardiovascular events (such as heart attack or stroke) is 29 percent lower in people with lower blood pressure than the control group," he told Reuters in a phone interview.

"We found that blood pressure lowering significantly reduces the high death rate in patients on dialysis, preventing one in five deaths compared to people who did not receive the treatment."

Experts do not know for sure how lowering the blood pressure of dialysis patients reduces their risk of death from cardiovascular disease but Perkovic offered a possible explanation.

"Toxins build up in the blood of renal patients, and maybe these accentuate the impact of (high) blood pressure," he said.

He hoped the analysis would persuade doctors to change the way they treat dialysis patients.

"Our study shows blood pressure lowering treatment should routinely be considered for individuals undergoing dialysis to protect patients from the high rate of cardiovascular disease such as heart attack and stroke, and to reduce their risk of dying," he added. (Reporting by Tan Ee Lyn; Editing by Phakamisa Ndzamela)

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