Keeping CD4 counts above 350 significantly reduces the risk of developing both AIDS- and non-AIDS-related health problems, according to a study published in the April 23 issue of AIDS. This finding lends further credibility to recent changes to adult HIV treatment guidelines moving the threshold for when to start HIV treatment from 200 to 350 CD4 cells.

Experts have long argued that ARV therapy comes with benefits and risks. While it can dramatically reduce the risk of dying of an AIDS-related disease, the longer survival it affords likely increases the chances of an HIV-positive person facing a non-AIDS-related illness, including those associated with other infections (e.g., viral hepatitis) and risk factors (smoking). While studies have confirmed this, research has also shown that people not on ARV therapy face a higher risk of non-AIDS cardiovascular-, cancer- and kidney-related diseases than those who are on ARV treatment. 

Jason Baker, MD, from the University of Minnesota in Minneapolis, and his colleagues reckoned that just as higher CD4 counts while not on ARV treatment lowers the risk of AIDS-related health problems, a healthy immune response to HIV therapy is also protective against non-AIDS-related diseases.  To test this hypothesis, Baker’s team analyzed data from the FIRST study, which ran between 1999 and 2002, comparing three different treatment strategies in 1,397 people living with HIV new to ARV treatment. One group started a non-nucleoside reverse transcriptase inhibitor (NNRTI)-based combination, a second group started a regimen including a protease inhibitor (PI), and a third group started a regimen containing both.

During the course of the study, 227 people developed an AIDS-related disease and 80 developed a non-AIDS-related disease, including cancers and cardiovascular, kidney and liver diseases. Baker’s team found that when people had a CD4 count below 200, despite being on treatment, their risk for developing an AIDS-related disease was nearly 14 times higher than in people with an on-treatment CD4 count above 350. Their risk of developing non-AIDS-related diseases was more than twice as high as in people with higher CD4s.

With an on-treatment CD4 count between 200 and 350, the risk of developing an AIDS-related illness was still higher than in those with counts on treatment above 350, but only twice as high, while the risk of a non-AIDS-related health problem remained twice that of those with CD4s above 350.

Baker’s group concludes by calling for studies investigating the benefit of starting ARV treatment at higher CD4 counts and for further studies examining the potential links between CD4s and non-AIDS-related diseases.