The VACS Index (Veterans Aging Cohort Study)…or What a Bunch of Old Soldiers Can Teach Us About HIV

By Barb Cardell – cross posted from The Well Projecjpeg

I recently attended the ACTHIV conference in Denver, thanks to a scholarship from The Well Project. ACTHIV is a nationwide conference for HIV treatment attended by providers, nurses, case managers, social workers, and researchers. Leading researchers in HIV care and prevention introduced some exciting new findings. But, what seized my imagination and turned me into a one-woman Veterans Affairs (VA) cheering squad and math Geek (with a lot of help from the internet) is a new way of following HIV progression and associated mortality by looking at “non-HIV” lab results such as the liver enzymes AST and ALT.

A little background, the VA system is the largest single HIV care provider in the United States working with over 20,000 HIV+ vets. They have several advantages over “traditional” HIV study sites. The VA has electronic medical records ensuring access to past and current medical records. They have an opt-out HIV testing policy that has a higher than average rate of HIV testing and as the Veterans Administration, they are privy to aspects of veterans lives that many civilians protect. These are all ideal conditions for a long-term observational study (a study that studies people but doesn’t dictate medications or treatments).

From 1997 to 2002, the Veterans Aging Cohort Study (VACS Index) recorded HIV-specific information for each patient: CD4 counts, viral loads and the occurrence of AIDS defining illnesses. They also tracked non-HIV specific lab results: hemoglobin (red blood cell that carries oxygen in your blood), transaminases (enzyme that can predict liver problems), platelets (cells in your blood that help with clotting), creatinine (high levels can indicate kidney problems) and hepatitis B and C infection) of close to 10,000 vets. Collaborating with the Yale School of Medicine, they discovered that using both the HIV and “non-HIV” related information; they could improve their ability to predict the risk of death from all cause mortality (doesn’t include accidents but everything else counts, stroke, heart attack, aneurism or cancer to name a few).

In 2003, a new arm of the study comparing HIV+ to HIV- participants began. They were matched in a cohort study (where participants have similar ages, genders, race and places of medical care, the only difference is their HIV status) to see how effectively these non-HIV biomarkers would predict a five-year mortality risk. As seen in the study results, these new indicators are pretty effective and the VACS Index was born.

Now, I don’t usually love math. I know enough to tip a waitperson and understand viral load log changes (a change in your viral load that is 10 times more or less than your previous test) but the equations that are used in the VACS index can be pretty obscure (take the square root of your ALT?). With a little help from the Internet, even a dedicated math-phobe like myself can puzzle through the seven components of the assessment and arrive at a VACS Index risk of 5 year mortality.

Next question, why on earth would I want to do this? Because, the VACS Index reflects a profound change in HIV care. Rather than looking at the usual CD4 and viral load that tell me how my disease is doing, I have a chance to understand the full story, the damage HIV (and yes, the treatments) have wreaked upon my body. This requires no extra tests, but I can see how anemia, liver injury, kidney functions and a hepatitis infection are challenging my body…telling me how my health is doing, the whole me, not just the virus. Sure, calculating your risk of death in five years is freaky and a bit terrifying but it is a chance to understand and KNOWLEDGE IS POWER!

With all this in mind, I pulled my head out of the sand and calculated my VACS Index score using my most recent lab results. Full disclaimer: I am not a Veteran. I may be comparing different lab tests that have different results. I am using the study in an unintended fashion. But, according to the Restricted Index (chance of death within 5 years based on age, CD4 and viral load.) I am at 0 % risk of death. That is pretty good! However, with the VACS Index, my risk rises to 22%. WHAT ?!!! Lots of only slightly elevated lab results show there might be something going on under the radar and that gets my attention.

I have an appointment with my HIV specialist, and I know what is going to happen. He will take a deep, calming breath but that doesn’t matter because he knows that we are a team. I am empowered! I advocate for myself and I think for myself. Any tool that helps me ask questions, understand my disease AND my body is a good thing.

I have too much living to do. I will not stand even a 22% chance that I won’t be here to do it.

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