Washington ? People who have the AIDS virus should start drug treatments sooner than current guidelines recommend, suggests a large new study that could change the care of hundreds of thousands of Americans.

The study found that delaying treatment until a patient’s immune system is badly damaged nearly doubles the risk of dying in the next few years compared with patients whose treatment started earlier.

Doctors have thought it would be better to spare patients the side effects of AIDS drugs as long as possible.

“The data are rather compelling that the risk of death appears to be higher if you wait than if you treat,” said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, which helped pay for the study.

If the results prompt doctors to change practice – as Fauci and other AIDS specialists predict – several hundred thousand Americans who are not taking AIDS drugs now would be advised to start.

The study was reported Sunday at an infectious diseases conference in Washington.

About 56,300 Americans are newly infected with HIV each year. The virus ravages T-cells – “helper cells” of the immune system that fight off germs. Once that happens, people can fall prey to a host of diseases that prove fatal.

Powerful drug combinations available since the mid-1990s have transformed HIV infection into a manageable chronic condition rather than the death sentence it once was. But they can cause heart and cholesterol problems, diarrhea, nausea and other side effects. They also must be taken faithfully or the drugs stop working.

That is why guidelines by the government and the International AIDS Society recommend that patients who are not yet having AIDS symptoms delay starting on the drugs until their T-cell counts fall below 350 per cubic millimeter of blood (healthy people have more than 800).

“There was this thinking, maybe the drugs were worse than the disease. If you could wait as long as you possibly could wait, you would have fewer side effects,” said Dr. Robert Schooley, of the University of California, San Diego.