HIV-infected patients who began treatment earlier than is normally recommended lived longer than those who underwent the standard regimen, a study found.

Patients who waited for levels of their immune cells to fall below recommended levels were 74 percent more likely to die in any year than those who started treatment earlier, said Mari Kitahata, a University of Washington AIDS researcher in Seattle who helped write the nationwide study of HIV patients' records.

Infectious disease doctors recommended in August that treatment start when the number of CD4 cells drops to 350 per milliliter of blood, up from an earlier standard of 200. The new study, reported today at an infectious disease meeting in Washington, may spark discussion on raising the standards and could increase the number of people on medication, said John Bartlett, at Johns Hopkins University in Baltimore.

"A lot of us are pretty convinced that the recommendation is going to 500," Bartlett, an HIV/AIDS doctor, said in an Oct. 23 telephone interview. "We'd be treating an enormously larger number of people than we are now."

A recommendation for earlier treatment would emphasize the importance of finding more undiagnosed patients and getting them into treatment programs, Bartlett said. States and health officials have been too slow to respond to government guidelines that call for testing all adults at least once for HIV, he said.

"The most effective program the U.S. could have is to test and treat," he said. "We have to get rid of the fear of testing."

Kitahata reported her findings at the Interscience Conference on Antimicrobial Agents and Chemotherapy. The study looked at patient records from 1996, when patients began taking drug combinations to keep virus levels at undetectable levels, through 2006. It compared death rates in 1,921 patients who started treatment when their CD4 level was 351 to 500 with 4,005 patients who started treatment when their CD4 levels were lower.

Based on the higher risk of death, Kitahata said she might personally recommend starting treatment at CD4 levels of about 450 to 500 per milliliter of blood.

"This information is very significant," Kitahata said in an Oct. 23 telephone interview. "Our goal is to have people live as long as possible with as high quality of life as possible."

After 1996, when combinations of antivirals were found to be effective for HIV patients, some doctors delayed giving them because they carried long-term side effects, such as heart disease, Bartlett said. Since then, new combinations have become available that minimize the side effects, and doctors have found that delaying treatment too long can put patients at risk of severe damage to the immune and nervous systems, he said.

About 1.1 million people in the U.S. are infected with HIV, the virus that causes AIDS, a potentially lethal immune disorder that leaves the body open to all kinds of infections, according to the U.S. Centers for Disease Control and Prevention in Atlanta. Roughly one quarter of those infected don't know it, and thus can't benefit from treatment.

Bartlett said he would wait for more evidence or a new recommendation from treatment experts before changing his practice.

"I have great faith in the process and the people who put these guidelines together," he said "Using collective talent has brought a lot to this disease."