Abstract and Introduction
Low-level viremia predicts viral rebound, but the absolute risk is low and the next clinical step is unclear.
Because of improvements in the sensitivity of viral-load assays, it is now possible to detect HIV RNA levels below 50 copies/mL. However, in patients on antiretroviral therapy (ART), the clinical implication of a detectable viral load <50 copies/mL (i.e., low-level viremia) is uncertain. To address this issue, investigators assessed whether low-level viremia, measured with an assay that has a detection limit of 3 copies/mL, is a predictor of viral rebound.
A total of 1214 HIV-infected patients with viral loads <50 copies/mL on ART were followed for 12 months in a prospective cohort study. On average, patients had received four previous regimens; only 23% were on initial therapy.
During the study, 2.6% of patients experienced viral rebound, defined as a confirmed viral load >200 copies/mL. Patients who had a baseline viral load of 3 to 50 copies/mL had a significantly higher risk for rebound during the following 4 months than those who had a baseline viral load <3 copies/mL (2.0% vs. 0.4%). The risk for rebound was particularly high (18%) in the small group of patients (73 total) who had persistently detectable HIV RNA values between 3 and 50 copies/mL.
Viral genotyping in 43 patients with HIV rebound revealed significant mutations in only 13 patients (30%), 5 of whom were on unconventional regimens (triple-nucleoside or two-drug regimens). The number of patients who achieved virologic resuppression without changing their regimens was not provided.
AIDS Clinical Care © 2012 Massachusetts Medical Society