Treatment Issues for HIV-Positive Womena

Treatment Issues for HIV-Positive Women

HIV Viral Loads and CD4 Counts in Women Versus Men

There are clearly many unique issues that affect HIV prevention strategies for women, and the same is true for HIV treatment. Once a person is diagnosed with HIV, clinicians depend on viral loads and CD4 counts to determine when a patient should start treatment and to determine if their medications are working.

It is generally assumed that a higher viral load means more viral activity in the body, and a higher CD4 count means a stronger immune system against HIV.

We aim for undetectable viral loads and higher CD4 counts in the context of antiretroviral therapy. However, these assumptions and treatment guidelines were based mainly on studies on men. We are now learning that the immune system in women and HIV may interact differently than they do in men. These findings have led to some changes in treatment guidelines, as summarized below.

Multiple studies have shown that women have lower levels of HIV (as measured by HIV RNA levels) in their blood than men do, even at the same CD4 counts.¹⁵ This means that at a certain CD4 count (usually at higher CD4 counts), men will tend to have a higher viral load than women. This difference can be as much as two to six-fold for HIV viral levels.

However, both men and women will progress to AIDS at the same rate. Another way to interpret this is that women are at increased risk of progression to AIDS when compared to men with the same viral loads, especially early on in infection. It is unclear why this phenomenon occurs, but these findings have led to important treatment guideline changes.

Prior guidelines recommended incorporating the HIV viral load to guide decisions regarding when to start treatment and when to modify therapy. However, that recommendation would mean that women would often get started on treatment much later than their male counterparts even though they had the same amount of immune suppression.

Guidelines have now changed to reflect that women often have viral loads that are much lower than men and the decision regarding when to start treatment is now made based on CD4 counts instead of viral loads.

Women also tend to have higher CD4 cell counts than men, at least early on in infection. This does not necessarily mean that they have stronger immune systems, because we have found that women can develop AIDS at higher CD4 counts than men. Some authors have argued that, because women have higher CD4 counts when they develop AIDS, perhaps they should be started on highly active antiretroviral therapy (HAART) at higher CD4 counts than men. More research is needed to determine how to use viral loads and CD4 counts in women to determine when to start antiretroviral (ARV) treatment.