Challenges in Achieving a Longer Life
The widespread use of potent combination anti-HIV therapy (commonly called ART) has led to dramatic declines in deaths due to AIDS-related complications across Canada and other high-income countries. Researchers expect that many HIV-positive people who take ART every day exactly as directed will likely have a near-normal lifespan.
What are the factors that can diminish survival among ART users today? To answer this question, researchers with the U.S. health maintenance organization Kaiser Permanente in California reviewed and compared health-related data from nearly 300,000 people. They found that certain factors played an important role in reducing survival among HIV-positive people, including the following -- co-infection with hepatitis-causing viruses, excessive intake of alcohol, substance use and tobacco smoking.
If HIV-positive people are to survive well into their senior years, doctors and nurses need to screen HIV-positive people for these issues. Importantly, the biological and psychological drivers of engagement in substance use also need to be addressed.
The Kaiser researchers amassed data between 1996 and 2011 on 24,768 HIV-positive people. In their database, they matched each HIV-positive person to data from about 10 other HIV-negative people of similar characteristics (such as age and gender).
The average profile of HIV-positive people upon entering the study was as follows:
- age -- 41 years
- 91% men, 9% women
- major ethno-racial groups -- 56% white, 21% black and 18% Hispanic
- main demographic groups -- 76% men who had sex with men, 16% men who had sex with women, 7% sharing equipment for injecting street drugs
- a positive test for hepatitis B virus (HBV) or hepatitis C virus (HCV) -- 12%
- ever engaged in drug or alcohol abuse -- 21%
- ever smoked -- 45%
- 46% were taking ART
- 40% initiated ART during the course of the study
In the case of HIV-positive people, as with reports from other high-income regions, the Kaiser researchers found that, as of 1996, death rates decreased and life expectancy began to increase.
The researchers performed calculations (in a manner similar to what life insurance companies do) to estimate life expectancy for a typical 20 year old at different points in time and arrived at the following results:
- An HIV-negative 20 year old could expect to live an additional 63 years, for a total life expectancy of 83 years.
- An HIV-positive 20 year old could expect to live an additional 19 years, for a total life expectancy of 39 years.
- An HIV-negative 20 year old could expect to live an additional 65 years, for a total life expectancy of 85 years.
- An HIV-positive 20 year old could expect to live an additional 53 years, for a total life expectancy of 73 years.
The Gap in Time
When one subtracts the differences in life expectancy between an HIV-negative person and an HIV-positive person in 2011, there is a gap of 12 years. In sub-analyses, researchers found that gaps in life expectancy existed regardless of gender, race/ethnicity or HIV risk group.
Other recent research has shown that starting ART when the CD4+ count is relatively high confers many health benefits. It is possible that people who have initiated ART in recent years at higher CD4+ counts may perhaps be somewhat healthier than people who initiated ART with older drugs further in the course of HIV disease. That is, people who initiated ART in the recent era are likely to have less injury to their immune system. To take this into account and reduce potential unintended bias, the Kaiser researchers decided to perform a sub-analysis by focusing on the most recent data, the years 2008 to 2011. They found that when participants initiated ART at CD4+ counts of 500 cells/mm3 or greater, the gap in life expectancy between them and their HIV-negative counterparts was about eight years.
When focusing on participants in this time period who initiated ART when their CD4+ count was at least 500 cells/mm3, researchers found the following:
- participants who did not have HBV or HCV -- the gap was 7.2 years
- participants who did not have drug or alcohol abuse issues -- the gap was 6.6 years
- participants who did not smoke -- the gap was 5.4 years
Based on these results, the researchers encouraged doctors and nurses to offer screening, treatment and counselling for the issues that can reduce life expectancy among HIV-positive patients. By making these interventions, doctors and nurses can help improve the lifespan and likely the quality of life of their patients.
There is still a gap in life expectancy calculations using data from up to 2011. However, in a few years the Kaiser database should have accumulated sufficient information from more recent years and a re-analysis of life expectancy should be done to see if gaps still exist.
Marcus JL, Chao C, Leyden W, et al. Narrowing the gap in life expectancy for HIV+ compared with HIV-negative individuals. Conference on Retroviruses and Opportunistic Infections, 22-25 February 2016, Boston, MA. Abstract 54