WASHINGTON (Reuters) - Heart bypass surgery may be less dangerous for older patients with diabetes than angioplasty, researchers reported yesterday.

Overall, there was not much difference, they reported in the Lancet medical journal.

But among patients aged 65 to 75 who had diabetes, the bypass surgery was markedly less deadly.

The study, paid for by the US Agency for Healthcare Research and Quality, is one of a series meant to help doctors and patients choose which treatment they want when several different options are available.

Mark Hlatky of Stanford University in California and an international team of colleagues studied the data from 10 different trials involving more than 7,800 patients.

The studies were all designed to see if there was any difference between bypass surgery, in which a vein is grafted to route blood around a clogged artery leading from the heart, and angioplasty, in which a blocked artery is stretched or scraped clean or propped open with a mesh tube called a stent.

Overall, 15 to 16 percent of the patients died. But patients with diabetes were 30 percent less likely to die if they got the bypass, Hlatky's team reported.

"Patients with diabetes, and older patients, might have a significant survival advantage if treated with (bypass)," they wrote.

And patients under 55 were 25 percent more likely to die with bypass than with angioplasty.

None of the trials used the newer, drug-eluting stents, which release medicines designed to keep the blood vessel from closing up around the device.

The US government will fund and conduct more such studies under a policy set by President Barack Obama.