In 2002, an estimated 3.1 million people died of AIDS . AIDS is caused by the Human Immunodeficiency Virus (HIV), which is transmitted between people through blood, semen, and vaginal fluid. HIV infects CD4 cells (immune cells that fight off infection), killing or damaging them so they are no longer able to function. Someone who has tested HIV-positive does not necessarily have AIDS. To diagnose AIDS, at least one of two criteria must be met: the CD4 cell count must drop below a predetermined level and/or the patient must be diagnosed with infections or cancers that signal an underlying deficiency in the immune system.

When the AIDS epidemic began in the 1980s, most people who tested HIV-positive would go on to develop AIDS. Treatments have since improved and the prognosis for people with HIV is much better.

HIV medications that have been approved by the FDA include reverse transcriptase (RT) inhibitors and protease inhibitors. Both inhibit the ability of the virus to replicate itself; RT inhibitors at an early stage and protease inhibitors at a later stage of the virus’ lifecycle. Used separately, these drugs quickly become ineffective due to an inevitable build-up of HIV resistance. Used together, however, they have dramatically decreased HIV-related illness and death since their combination in 1996. Hence the name: highly active antiretroviral therapy (HAART).

However, because HAART is expensive and not without its serious side effects, some researchers have questioned whether HAART would be able to sustain its beneficial effects over the long term in a large population of patients. To date, there has been a lack of longitudinal studies that monitor the effects of HAART over several years.

A new study in the July 5, 2003 issue of The Lancet followed a group of people with HIV and/or AIDS from 1994 to 2002 and found that the reduction in HIV-related illness and death produced by HAART was sustained for several years. The researchers determined that the incidence of AIDS or death decreased drastically until September 1998, and continued to fall by 8% every six months thereafter.

About the Study

The researchers recruited 9,803 patients from 70 HIV/AIDS clinics in Europe, Israel, and Argentina. The patients were divided into three groups, depending on when they were recruited:

  • The pre-HAART era (1994-1995)
  • Early-HAART (1996-1997)
  • Late-HAART (1998 onwards)

The researchers collected information on the patients’ CD4 counts (a marker for disease progression) and treatment regimens every six months. Dates of deaths and AIDS diagnoses were also documented. With this information, the researchers calculated the incidence of AIDS or death for every six-month period during the study.

The Findings

Over the course of the study, the patients’ average CD4 count rose steadily, from 164 cells per microliter (cells/µL) in 1994–1995 to 424 cells/µL in 2001–2002. Furthermore, the combined AIDS and death rate fell steadily over time, and by September 1998, it was about a tenth of that at the start of the investigation in 1994. After September 1998, the combined AIDS and death rate continued to drop an estimated 8% every six months.

When comparing the pre-HAART era, early-HAART, and late-HAART, the researchers found dramatic decreases in AIDS and death rates. The incidence of AIDS was about 50% lower in late-HAART when compared with early-HAART. The incidence of death also decreased significantly from the pre-HAART era to late-HAART.

Since this study was conducted at specific centers in Europe, Israel, and Argentina, it may not be representative of HIV and AIDS patients in all regions of the world. The experience of clinicians, treatment decisions, and availability of HAART regimens varies greatly, but because this study included a large number of clinics, it is likely a reasonable representation of other populations.

How Does This Affect You?

Although there was a dramatic decrease in the incidence of AIDS and death when HAART was first introduced in 1996, skeptics were concerned that problems with compliance and potential adverse effects might diminish its effectiveness over the long run. This study showed that these issues have not yet hindered the clinical success of HAART. In fact, since HAART was introduced, there has been a sustained and dramatic decrease in HIV-associated illness and death.

Since AIDS and death rates continued to decrease in the late-HAART period, it is possible that HAART has long-lasting benefits that take some time to appear. Longer-term follow-up studies will be necessary to monitor the effects of HAART over time. Still, HAART is not a cure for AIDS and prevention programs remain the key to managing the ongoing HIV epidemic worldwide.