Updated

An American diagnosed with the AIDS virus can expect to live for about 24 years on average, and the cost of health care over those two-plus decades is more than $600,000, new research indicates.

Both life expectancy and the cost of care have risen from earlier estimates, mainly because of expensive and effective drug therapies, said Bruce Schackman, the study's lead author.

The research found that the average annual cost of care is about $25,200 — nearly 40 percent higher than a commonly cited estimate from the late 1990s.

The new research also updates other studies from the 1990s, when life expectancy for HIV-infected people was closer to 10 years.

The study could influence how much state and federal governments appropriate for HIV and AIDS care and prevention in the future, some HIV policy experts said.

"They're going to have to take into account medical advances that have extended people's lives," agreed Schackman, assistant professor of public health at New York's Weill Cornell Medical College.

The study appears in the November edition of the peer-reviewed journal, Medical Care.

A 1993 estimate of life expectancy for a symptomless person infected with HIV was less than seven years.

But since the mid-1990s, about two dozen HIV-fighting antiretroviral drugs have come onto the market that have essentially turned HIV from a death sentence into a chronic disease.

Physicians now understand life expectancy after HIV diagnosis to be two decades or more, and the new study supports that belief.

"It's nice to see that in writing," said Dr. Carlos del Rio, co-director of Emory University's Center for AIDS Research.

The researchers drew most of their data from 18 medical practices across the United States that provide care for 14,000 patients. The researchers looked at the records of about 7,000 of those patients.

They used a computer simulation model to project HIV medical care costs, and concluded the average lifetime cost of HIV care is $618,000 per person.

That figure is roughly equivalent to lifetime cost estimates for heart disease and some other chronic conditions in women, who incur more costs than men because they live longer, the researchers said.

The researchers estimated the monthly cost of care at $2,100, with about two-thirds of that spent on medications. That equates to $25,200 a year. In 1998, the average annual cost was $18,300, according to an older study.

The difference is not just inflation — the costs of improved and more expensive HIV medications account for much of the difference, Schackman said.

For example, a typical regimen for an HIV patient beginning treatment includes the drug efavirenz, which blocks a certain protein that HIV needs to make copies of itself. It also includes tenofovir and emtricitabine or some similar drug, which helps keep the AIDS virus from reproducing.

The monthly cost just for that regimen was about $1,140 in 2004, Schackman and the other researchers said. If that treatment doesn't work or stops working, the patient is switched to more expensive arrays of drugs.

In their cost estimates, the researchers aimed high, basing their numbers on the best available drugs and the best standards of care. But that's not always what's provided, some HIV policy experts noted.

For example, a 2003 federal study concluded that only 55 percent of HIV patients who should have been on virus-fighting medications were actually getting them.

"This is really an optimistic scenario" in the study, and the true cost is probably lower, said Jennifer Kates, director of HIV policy for the Kaiser Family Foundation.

However, she added that since people living with HIV should be getting optimal care from doctors experienced in treating HIV, the study's expectations are reasonable, she added.