B.C. researcher Robert Hogg knew that a frequently used cocktail of drugs was helping people with HIV live longer than expected. He was also well aware of studies, regional in focus, that showed drugs taken in combination were keeping AIDS at bay.

Although treatment had to be for life, evidence was growing that people with HIV could live many years with the right mix of medication. Prospects for a longer life were improving.

But Hogg did not know how much better. So in the late 1990s, he undertook, along with researchers from Western Europe, the U.S. and Canada, to find out the impact of AIDS drugs on life expectancy.

Robert Hogg, HIV researcher at Simon Fraser University, B.C. (Courtesy Robert Hogg)

Hogg and others published their findings in the July 26 issue of the medical journal Lancet. Their study found that a combination of antiretroviral drugs increases the life expectancy of HIV patients in high income countries by more than 13 years.

That means a patient who began drug treatment at age 20 could expect, on average, to live about 49 years longer to reach 69.

That is still less than the life expectancy for the general population in most Western countries, which is about 80 years. But for a disease that had been seen as a cruel and short life sentence only a generation or so ago, this was a remarkable leap forward.

Women do better

The researchers looked at 43,000 patients in 14 studies in Western Europe, Canada and the U.S., and from 1996 to 2005, they followed the patients in these studies.

Their work found that women with HIV had higher life expectancies than men with HIV, while patients who had contracted HIV through intravenous drug use and patients treated later in the course of their infection and whose immune systems were severely compromised had lower life expectancies than those of other groups.

"People are living longer with HIV," Hogg said an interview from Vancouver. "It's a lifelong disease and people are living a long time with it. But they are still not living as long as other people."

Hogg, director of the population health program at the B.C. Centre for Excellence in HIV/AIDS in Vancouver and a Simon Fraser University health sciences professor, said the study is significant because it's the largest of its kind.

It's also international in scope. Previous studies trying to answer the same question were national or regional.

He said he thinks the findings of the study could prompt a shift in thinking, given that members of the public may have had an idea that people with HIV were living longer but they did not know it is by more than a decade. He says the study is proof.

A treatable disease

Hogg says the study also has implications for governments that provide funding for research, for caregivers who can expect their patients to live longer and for the drug treatments themselves. "In terms of treatment, it's a lifelong endeavour."

The researchers looked at three groups of patients who started a combination of antiretroviral drugs over three periods, in 1996-99, 2000-02, and 2003-05. They compared changes in mortality and life expectancy among the patients with HIV over these periods. They calculated what they called "potential years of life lost" and mortality rates.

What they found was that: "Over the past decade, combination therapy regimens have become more effective, better tolerated and have been simplified in terms of dosing. Clinical trials and observational studies have shown profound reductions in mortality and morbidity in patients infected with HIV as a result of combination antiretroviral therapy.

"This decrease in mortality is particularly apparent in industrialized, high income countries where access to health care and antiretroviral treatments is more readily available."

The wealthy world

The researchers say they wanted to gain a better understanding of the effect of HIV on life expectancy given the increasing effectiveness of drugs in combination. "These advances have transformed HIV from being a fatal disease, which was the reality for patients before the advent of combination treatment, into a long-term chronic condition."

They conclude: "In summary, the results of this study indicate that people living with HIV in high-income countries can expect increasing positive health outcomes on combination antiretroviral therapy. The marked increase in life expectancy since 1996 is a testament to the gradual improvement and overall success of such treatment."

Hogg says the next step is to compare life expectancy rates of people with HIV in high income countries with that of those in low income countries.

The United Nations estimates that 33 million people around the world are living with HIV. It says about two million died of AIDS in 2007, while about 2.7 million were newly infected last year. AIDS continues to be the leading cause of death in Africa.

The UN estimates that three million people are receiving antiretroviral treatment in low and middle income countries.

According to the UNAIDS "2008 Report on the global AIDS epidemic," the number of people taking AIDS drugs has increased tenfold in the last six years. About 300,000 took AIDS drugs in 2003, while about three million did so in 2007.

But the agency, a joint venture of the UN that brings together the resources of 10 UN organizations, says millions do not have access to the necessary drugs.

Both the life expectancy study and UN global AIDS epidemic report were released on the eve of the 17th International AIDS conference in Mexico City that is expected to draw about 25,000 participants from Aug. 3 to 8. The theme of the conference is Universal Action Now. It's the first international AIDS conference to be held in Latin America.

"AIDS 2008 is taking place at a unique moment in the epidemic, when there is widespread consensus on the need to ensure universal access to HIV prevention, treatment, care and support by 2010," Dr. Pedro Cahn, co-chair of the conference, said in a news release.

"What we now need is action on the part of all stakeholders, including continued investments in HIV research and a commitment to implementing evidence-based interventions."

Hogg, who is not attending the conference, agreed. He said a vaccine is likely at least 10 years away and more emphasis needs to be placed on preventing the spread of the virus. And if people with HIV are living longer, then access to drugs is vitally important.

"If there is such a huge benefit, why not put them on treatment?"

Source: CBC News - http://www.cbc.ca/canada/story/2008/07/31/f-hiv-life-expectancy.htm