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Aging and HIV: Emerging Issues in Research, Treatment and Care

Summer/Fall 2010

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Table of Contents


Introduction

Thanks to better HIV treatments -- and the efforts of treatment advocates -- people are living longer with HIV. As HIV positive people get older, and as increasing numbers of people acquire HIV at an older age, the medical, emotional and social issues typically associated with aging are compounded by HIV-related challenges.

To address these issues, San Francisco AIDS Foundation held an official satellite session at the XVIII International AIDS Conference on July 19, 2010, in Vienna, Austria. The session included a series of presentations on current epidemiology and research, followed by a panel discussion with older HIV positive individuals and a dialogue with audience members.

The satellite session was cosponsored by Gay Men's Health Crisis and amfAR, the Foundation for AIDS Research. Dr. Rowena Johnston, Vice President and Director of Research at amfAR, gave the audience an epidemiological overview of HIV/AIDS in older individuals around the world. She was followed by Dr. Amy Justice, Associate Professor of Internal Medicine at Yale Medical School and Principal Investigator for the Veterans Aging Cohort Study, who offered a framework for understanding the multiple illnesses that affect people aging with HIV. Dr. Glenn Treisman, Director of the AIDS Psychiatry Program at Johns Hopkins University School of Medicine, spoke on the interactions between HIV disease and psychiatric conditions.

These presentations were followed by a discussion among HIV/AIDS advocates who are themselves over the age of 50 and living with HIV. Dr. Michael Siever, Director of Behavioral Health Services at San Francisco AIDS Foundation, and Ms. Sylvia Young, Peer Advocate Program Manager at Women Organized to Respond to Life-threatening Disease (WORLD) in Oakland, California, were joined by Ms. Siphiwe Hlophe, Founder and Director of Swaziland Positive Living (SWAPOL).

Following are excerpts from the presentations and the panel and audience discussions, highlighting important issues and urgent questions around aging and HIV.


Epidemiology of HIV and Aging

"As antiretroviral therapy becomes more widely available, the proportion of people with HIV who are over 50 will absolutely grow."

-- Rowena Johnston

In her overview presentation, Dr. Rowena Johnston cited a report from the Centers for Disease Control and Prevention (CDC) indicating that, in the United States, 28% of new HIV diagnoses in 2006 were among people over 45 years of age. Mathematical models suggest that half of all HIV positive individuals in the U.S. will be over 50 by the year 2015.

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Data collected by the Joint United Nations Programme on AIDS (UNAIDS) define "adults" as people between 15 and 49 years of age, making it difficult to find information about HIV infection in people over 50 outside the U.S. But a study described in the journal Clinical Interventions in Aging suggests that about 7% of the world's HIV positive population (roughly 2.3 million people) is 50 or older. That proportion will increase as antiretroviral therapy becomes more widely available around the globe and more people have access to life-saving treatment. Already, Johnston said, there are significant populations of older adults living with HIV in Kenya, Jamaica, India, and parts of East Asia.

Where data about HIV in older adults are available, they tend to reflect prevalence (the number of people living with HIV disease) rather than incidence (the number of people newly infected), making it unclear whether HIV was acquired earlier in life or after the age of 50. This gap in knowledge poses a problem, as the medical needs of individuals newly infected with HIV in older age tend to differ from those of older adults who have lived with the virus for many years.

There is also a great need for HIV prevention efforts among older populations. HIV prevention messages rarely target older individuals because of a common assumption that they don't have sex -- a misconception flouted by a recent study published in the New England Journal of Medicine showing that 73% of people aged 57 to 64 years are sexually active. "I think that probably comes as a surprise to a lot of people," said Johnston. Yet older adults often do not consider themselves at risk for HIV or other sexually transmitted infections; Johnston cited an Australian study suggesting that few older people use condoms or seek HIV testing.

As antiretroviral therapy becomes more widely available and people live longer with HIV, Johnston concluded, more information on the epidemiology of HIV and aging will be necessary to adequately meet the HIV treatment and prevention needs of older adults around the world.


Comorbidities Associated With HIV and Aging

"The question really is, 'What's the total burden of disease, and how do we try to minimize its effects on people's quality of life and survival?'"

-- Amy Justice

Between 20% and 75% of deaths among HIV positive individuals on antiretroviral treatment are now due to causes other than the AIDS-defining conditions specified by the CDC, explained Dr. Amy Justice, citing data from several studies showing that major causes of death among people with HIV are attributable to alcohol use, liver disease, cardiovascular disease, cancer and renal disease. She stressed, however, that while these illnesses are not considered AIDS-defining conditions, they are not necessarily unrelated to HIV disease.

Differences in HIV-related mortality between younger and older age groups cannot be explained by age alone. "Clearly, folks who have HIV infection -- and people who have lived an extended period of time exposed to HIV infection -- are biologically older than people who are newly infected or are not infected," Justice explained, and life expectancy may be shorter even among optimally treated individuals.

Researchers once thought that antiretroviral drug toxicities accounted for the continued higher risk of illness and death among treated patients. But results from the Strategies for Management of Antiretroviral Therapy (SMART) study, first published in 2006, suggested otherwise. In this landmark study, individuals who interrupted antiretroviral treatment when their CD4 counts exceeded a set threshold still had more deaths and more AIDS-defining and non-AIDS-defining conditions than study participants who stayed on continuous treatment, suggesting that long-term exposure to the virus itself accounts -- at least in part -- for the higher rates of illness and death seen among HIV positive individuals.

Today, researchers believe that HIV increases the risk of many "non-AIDS conditions," and chronic inflammation and immune activation appear to play a significant role (see "Inflammation and Immune Activation," below). The relative risk contributed by HIV infection is modest compared with other established risk factors for these conditions, but the effect of HIV increases over time: the longer an individual has the virus, the greater his or her risk for such conditions compared with a non-infected person.


Inflammation and Immune Activation

When the body is infected with bacteria or viruses (such as HIV), cells in the immune system produce proteins called cytokines. These proteins act like chemical "messengers" and help organize the body's immune response. Some cytokines trigger inflammation, which involves the transport of cells and fluids to the site of the injury; this causes the warmth, redness, swelling and soreness you may notice around a cut as it heals.

Inflammation can occur not only at the level of your skin or in response to a visible injury, but also in organs or body systems such as the immune system or the central nervous system -- and may last far longer than the time it takes for a cut to heal. Chronic inflammation, which is now known to be associated with HIV infection, persists over time and involves the continued healing and destruction of cells and tissues. This type of inflammation is thought to be linked to heart disease and other life-threatening conditions.

Like inflammation, immune activation is appearing more and more frequently in the HIV literature. Soon after HIV infection occurs, massive numbers of immune cells in the gut are destroyed, allowing bacteria that normally live in the intestines to leak into the bloodstream -- a process called "microbial translocation." HIV is also thought to interfere with certain cells, called "regulatory T-cells," which are essential to halting immune responses once an infection is eliminated from the body. Both microbial translocation and the dysfunction of regulatory T-cells appear to contribute to immune activation, and to an overstimulated and overworked immune system.

The list of comorbidities (diseases or conditions that coexist with a primary disease) associated with HIV includes diseases of the lungs, liver, kidneys and heart and blood vessels, as well as neurological conditions and bone diseases. Clinicians with HIV positive clients need to carefully monitor for early signs of these non-AIDS conditions, Justice said, because they can be used to predict HIV disease progression and help providers intervene and work with patients to improve life expectancy and quality of life. For example, some conditions may justify starting antiretroviral therapy early, and conditions such as anemia may become important indicators of HIV disease progression.

Justice also acknowledged that drug toxicities complicate treatment for HIV positive individuals with comorbid conditions, and stressed that individualized care is becoming increasingly important. "If someone already has renal injury, we probably want to avoid drugs that are going to add to that renal injury, but all else equal, those drugs may actually help reverse some of that injury," she explained. "It's getting more complicated, in the sense of the balance that we need to make and the tailoring that we need to do for each individual patient who comes in."

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This article was provided by San Francisco AIDS Foundation. It is a part of the publication Bulletin of Experimental Treatments for AIDS. Visit San Francisco AIDS Foundation's Web site to find out more about their activities, publications and services.
 

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