Incomplete Viral Suppression Raises Death Risk in HIV Patients

The current standard of treatment for people diagnosed with HIV is to get them onto a regimen of antiretroviral drugs (ART) as soon as possible to enable viral suppression. Typically, ART allows these patients to live a greatly lengthened lifespan and avoid developing full-blown AIDS. But, viral suppression can be incomplete or delayed in certain individuals. What happens in those cases? A team of scientists set out to find the answer.

Researchers from the University of North Carolina at Chapel Hill and several other universities looked at data from almost 8000 HIV patients who began ART between 1998 and 2013. The patients’ viral levels were assessed 6 months after they began therapy to provide a baseline measurement, and they continued to be followed until either they died, 10 years had passed, or the study officially ended.

At 6 months post ART initiation, a total of 57% of the study participants had viral load measurements below 20 copies/mL, the minimum level of detection, indicating that ART was working. Viral loads of 1000 copies/mL were seen in 15% of participants. The rest had viral loads between 20 copies/mL and 999 copies/mL.

Ten years after first being assessed, the risk of death for patients who had viral loads between 20 copies/mL and 40 copies/mL at baseline was 14%, scarcely higher than the death risk for patients whose 6-month measurement was less than 20 copies/mL. The death risk was notably elevated for subjects whose viral loads at 6 months were higher: 20% for patients with viral loads between 400 copies/mL and 999 copies/mL, and 23% for patients with viral loads of 1,000 copies/mL or more. Overall, there was a 44% increase in the risk of death for subjects with viral loads between 200 copies/mL and 999 copies/mL. The scientists could not discern a particular viral-load level between 30 copies/mL and 500 copies/mL at which a steep increase in the 10-year mortality rate became apparent, but there was a gradual increase once subjects hit the 130 copies/mL threshold.

“We observed a clear pattern of increasing 10-year mortality risk with increasing viral load, based on one viral load measurement under 1000 copies/mL after 6 months of therapy,” the authors write. “We also observed that a single viral load measurement at or above 1000 copies/mL, 6 months after ART initiation was strongly associated with 10-year mortality. This suggests that a single viral load measurement collected 6 months after initiating ART remains highly informative regarding the risk of death over 10 years.”

The researchers note that HIV-positive individuals who have detectable viral loads after 6 months of ART may be dealing with drug resistance, drug interactions that impede the efficacy of ART, nonadherence when it comes to taking their medication as directed, or some other factor causing a less than optimal response. Those individuals with a viral load between 400 copies/mL and 999 copies/mL are at notably greater risk than those with lower viral loads. ‘[O]ccurrences of viral loads in this range may need to be treated similarly as viral loads that exceed 1000 copies mL,” the authors write. “Given the importance of rapidly achieving virologic suppression after initiating treatment, further investigation of the causes of unsuppressed viral loads between 400 and 999 copies/mL is warranted.”

Laurie Saloman, MS, is a health writer with more than 20 years of experience working for both consumer and physician-focused publications. She is a graduate of Brandeis University and the Medill School of Journalism at Northwestern University. She lives in New Jersey with her family.