Starting antiretroviral (ARV) treatment early—perhaps before CD4 counts drop below 500—significantly reduces the risk of death, according to a study published April 1 in The New England Journal of Medicine.

The question of when to start ARV treatment is a hot topic in HIV research, and not without some degree of disagreement among experts. A few studies have now shown an increased risk of problems such as heart attacks and non-AIDS-related causes of deaths in people who waited to start treatment until their CD4 counts dropped to 350. Some researchers feel that such findings are sufficient proof that treatment should be offered to people with HIV sooner, while others feel that there simply isn’t enough data to warrant significant changes to treatment recommendations currently in place.

To determine the potential benefit of earlier treatment initiation, Mari Kitahata, MD, MPH, from the University of Washington’s Center for AIDS and STDs in Seattle, and her colleagues examined the medical records of HIV-positive patients enrolled in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) study. Preliminary data from this study were first reported in October at the 2008 joint meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) and the Infectious Disease Society of America (IDSA) in Washington, DC.

In the published analysis, Kitahata’s team examined the records of 9,155 HIV-positive patients who were followed between 1996 and 2005 and who had CD4 counts over 500. Of these, 2,220 started ARV therapy with a CD4 count over 500, while 6,935 waited to start treatment until their CD4 count dropped below 500. In this analysis, the rate of death was 94 percent higher in those who waited to start therapy than in those who started treatment immediately, with a CD4 count above 500.

Older age, a history of injection drug use, and coinfection with hepatitis C virus (HCV) were all associated with a higher risk of death. However, even when accounting for these, the rate of death was still higher among people who waited to start ARV therapy in accordance with today’s official recommendations.

The authors encourage further study to verify whether their results should be used to update official treatment guidelines to recommend  that most people with HIV start treatment early.