A 20-year-old, HIV-infected individual on treatment who is living in the U.S. or Canada can reasonably expect to live into his or her early 70s, which is slightly lower than the U.S. general average of 78 years, according to a study presented at CROI 2012. However, there were notable differences in life expectancy depending on several factors, including transmission group, race and baseline CD4+ cell count.
The study, entitled "Temporal Changes in Life Expectancy in HIV-Positive Individuals in North America" and presented by Robert Hogg, Ph.D., of the BC Centre for Excellence in HIV/AIDS, is the first to characterize life expectancy numbers for people living with HIV in the U.S. and Canada. Last year, a European study found an average life expectancy for a person living with HIV was 71.5 to 75 years. And a collaborative study published in 2009 found that, across Canada, Western Europe and the U.S., average life expectancy for a person who began HIV treatment between 2003 and 2005 was approximately 70 years.
For the current study, researchers analyzed NA-ACCORD data from 23,739 people, all of whom were treatment naive and at least 20 years old when they started HAART. They found that the average life expectancy for a person living with HIV at age 20 gradually increased from 1996 to 2007, going from 34.4 years in 1996-1999 to 47.1 years in 2006-2007. This increase is significant but still lower than the 58.8-year average for the U.S. general population, according to the U.S. Centers for Disease Control and Prevention.
However, there were some confounding factors, which included race, transmission group and baseline CD4+ cell count.
Among the population studied, African-American life expectancy at age 20 (41.0 years) was lower than that of whites (50.0 years) and Hispanics (52.6 years).
Among transmission groups, life expectancy at age 20 for injection drug users was the lowest at 28.1 years, while it was 51.6 years for MSM (men who have sex with men) and 47.7 for heterosexuals. (The study did not differentiate between HIV-related and non-HIV-related causes of death for injection drug users.)
In terms of baseline CD4+ cell count, all groups that started treatment with a CD4+ cell count above 200 cells/mm3 were found to have similarly high numbers for life expectancy at age 20. The best numbers were seen in those who had a baseline CD4+ cell count between 200 and 349 (52.4 years) or between 350 and 499 (52.6 years), followed by those who started treatment with a baseline CD4+ cell count above 500 (46.4 years).
Concerning the slight drop in life expectancy for those who started treatment at a high CD4+ cell count, lead researcher Hogg noted: "Those that started over 350 in this analysis did so prior to recent changes in guidelines and are likely people starting because of other health issues."
Unsurprisingly, those who started treatment with a baseline CD4+ cell count below 200 had a lower life expectancy. Those who started with a CD4+ cell count between 100 and 199 had a life expectancy at age 20 of 44.2 years, which is comparable to the other groups. But for those with a baseline CD4+ cell count below 100, life expectancy at age 20 was significantly lower, at 29.0 years.
The study did not indicate whether these numbers had implications for the "when to start" and "test and treat" debates.
Overall, the study concluded that life expectancy for those on HIV treatment has increased over time. But Hogg noted that more research still needs to be done to address the differences among transmission groups, race and baseline CD4+ cell counts. "Over the next few months, we hope to complete this paper -- other work will look at disease burden," he said.
CORRECTION <03/30>: An earlier version of this article stated that the 47.1-year life expectancy for a person living with HIV at age 20 was "slightly" lower than the 58.8-year U.S. general population average. We have corrected the text to reflect that while the life expectancy increase from 34.4 to 47.1 years is significant, it is still lower than the 58.8-year average for the general population.