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Single measures of viral load not effective for assessing HIV suppression status

The percentage of HIV-positive individuals with durable viral suppression may be overestimated when calculated by single measures of viral load, according to findings published in Annals of Internal Medicine.

“The most common measure of HIV suppression in clinical and surveillance studies is whether a patient’s most recent viral load was less than 200 copies/mL during the preceding 12 months,” Nicole Crepaz, PhD, from the CDC, and colleagues wrote. “This single-value measure provides only a snapshot of suppression status and does not capture changes in viral load over time. Persons who are suppressed according to their most recent viral load measurement may still transmit HIV if their suppression status changes.”

Crepaz and colleagues used data from the National HIV Surveillance System to investigate the efficacy of a single measure of viral load for understanding long-term suppression and to evaluate the cumulative HIV burden for understanding the transmission risk. A total of 630,965 individuals aged 13 years and older who were diagnosed with HIV through 2013 from one of 33 jurisdictions were included. The researchers calculated the proportion of individuals with HIV whose last viral load was less than 200 copies/mL in 2014 using data on participants’ sex, age, transmission category and race/ethnicity. They also calculated the percentage of participants with durable viral suppression (less than 200 copies/mL of viral load) or who never achieved viral suppression (greater than 200 copies/mL of viral load) in 2014, as well as copy-years of viremia.

Data from the most recent tests in 2014 indicated that 57.3% of all HIV-positive individuals had a suppressed viral load, 47.6% had durable viral suppression and 8.1% never achieved viral suppression. Women, blacks, younger individuals and individuals with HIV not from male-to-male sexual contact were more likely to not have viral suppression or durable viral suppression. There was an average of 17,530 copy-years of viremia for the participants who never achieved viral suppression (n = 51,114) and 56.3% of these participants had at least two tests in 2014 for viral load, suggesting that they most likely received regular care for their infection.

“Our results confirm those of other studies,” Crepaz and colleagues concluded. “Single measures of viral load overestimate how many persons with HIV infection have durable viral suppression (20% relative difference). In addition, some persons who seem to have received regular care for HIV infection in 2014 still had viral loads high enough to substantially increase transmission (>10,000 copies/mL). These findings emphasize the importance of routine monitoring of viral suppression status and of more effective delivery of appropriate therapy in response to the results of such monitoring.” – by Alaina Tedesco

Disclosure: The authors report no relevant financial disclosures.