The Relationship of Pre- and Post-Treatment Laboratory Tests with Outcomes for Women Starting Treatment for HIV Infection

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The summary below is from the full report titled "The Prognostic Importance of Changes in CD4⁺ Cell Count and HIV-1 RNA Level in Women after Initiating Highly Active Antiretroviral Therapy." It is in the 17 February 2004 issue of Annals of Internal Medicine (volume 140, pages 256-264). The authors are K. Anastos, Y. Barrón, M.H. Cohen, R.M. Greenblatt, H. Minkoff, A. Levine, M. Young, and S.J. Gange.

What is the problem and what is known about it so far?

Human immunodeficiency virus (HIV) is the cause of AIDS. AIDS is a potentially deadly illness that interferes with the body's ability to fight off infection and certain types of cancer. Treatments containing multiple drugs (antiretroviral therapy) have greatly improved outcomes for HIV-infected patients. Regimens that contain powerful drugs called protease inhibitors can be particularly effective. These regimens are known as highly active antiretroviral therapy or HAART. Doctors use blood tests called CD4 count and viral load to determine when to start treatment for HIV infection and to monitor patients who are receiving treatment. CD4 cells are involved in fighting infection; they decrease as the disease advances, so a higher count is better. Viral load is a measure of the amount of HIV virus in the blood. It increases as the disease advances, so a lower load is better. CD4 cell count and viral load predict outcomes in HIV infection, but it has been uncertain whether the values of these tests before treatment or after treatment are best for predicting how patients will respond.

Why did the researchers do this particular study?

To see whether pre- or post-treatment laboratory tests are the best way to predict how well patients will respond after starting HAART for HIV infection.

Who was studied?

1132 women with HIV infection who started HIV treatment during the course of a large study of HIV infection in women.

How was the study done?

The researchers tested patients' blood for CD4 cell counts and viral load before and after treatment. They then examined the relationship between the laboratory tests and the women's risks for developing an AIDS-defining illness or dying over the next 4 years.

What did the researchers find?

The post-treatment laboratory tests were more accurate predictors of development of an AIDS-defining illness or death than were pretreatment values.

What were the limitations of the study?

This study did not examine the side effects of HAART for HIV infection.

What are the implications of the study?

A poor pretreatment CD4 cell count and viral load does not mean that a patient will respond poorly to treatment. Patients whose CD4 cell counts and viral loads respond favorably to treatment are likely to do well.