London ? Methotrexate, a key drug for rheumatoid arthritis, could help people with the crippling disease live longer, new research suggests.

Methotrexate, originally a cancer drug, has been used to fight rheumatoid arthritis for about 15 years. Since then it has been proven to slow progression of the inflammatory disease and to make patients feel better, but a new study provides the first hint it may also save lives.

Experts said the study, published this week in The Lancet medical journal, was encouraging but did not provide definitive proof.

Rheumatoid arthritis strikes about 1 percent of people, usually in middle age.

People with the disease tend to die about 10 years sooner than normal, according to Dr. Theodore Pincus, a prominent rheumatoid arthritis researcher from Vanderbilt University in Nashville, Tenn.

It is not the type of arthritis common in the elderly because of aging. It occurs when the immune system goes awry and attacks the joints, causing severe inflammation in the lining of the joints, pain and stiffness. It is also linked to an increased risk of heart disease.

Scientists believe people with rheumatoid arthritis have shorter life spans partly because they face increased chances of getting heart disease and dying from it.

The latest study, conducted by Dr. Frederick Wolfe of the Arthritis Research Center Foundation at the Kansas University School of Medicine, found that patients on methotrexate were 60 percent less likely to die prematurely than those not getting the drug.

They were 70 percent less likely than people not on the drug to die from heart disease.

Experts said that finding bolsters the growing body of evidence that inflammation might play a role in heart attacks and that anti-inflammatory medication might ward them off.

Methotrexate works by switching off the underlying inflammation caused by the immune response.

Dr. David Scott, professor of clinical rheumatology at Guy’s, King’s and St. Thomas’ Medical School in London, said the survival findings echo what doctors have suspected.

“If you go back 20 years when people had little treatment for their rheumatoid arthritis, they did very badly. Death was common,” said Scott, who was not connected with the research. “There’s no doubt that nowadays it seems a lot better, inasmuch as not so many people seem to be dying and patients seem to be doing a lot better overall.”

The biggest change in the last decade in rheumatoid arthritis has been the widespread use of methotrexate, he said.

“This would seem to be a drug treatment effect, but you can never be certain that it isn’t that the disease is getting milder,” he said.

Part of the uncertainty comes from the way the study was conducted, other experts said.

It involved 1,240 people with rheumatoid arthritis seen at a specialist arthritis center between January 1981 and December 1999.

A total of 588 of the patients were put on methotrexate, at their doctors’ discretion. Those more ill tended to get the drug.

By the end of the study, 191 of the patients had died, 72 of whom were on methotrexate.

Wolfe adjusted statistics to take account of the fact that the methotrexate group was sicker, but experts say the study’s method could not rule out that factors other than methotrexate could have been at work.