title: Increased risk of virologic rebound in patients on antiviral therapy with a detectable HIV load <48 copies/mL.
abstract: We investigated the independent effects of HIV-1 "target not detected" measurements versus those that were detectable but below the limit of quantification by Taqman RT-PCR assay on subsequent viral rebound as there are conflicting data regarding the clinical implications of arbitrary or isolated low-level viremia. Cox proportional hazard regression modeling was used to investigate the independent effects of the first HIV-1 load measurement after introduction of the Taqman RT-PCR assay (time-point 0 [T0]), pre-T0 viral loads, CD4 T cell count, race/ethnicity, gender, age and NNRTI use on risk of a confirmed VL >50, >200, >400 and >1000 copies/mL at 22 months follow-up in analyses of all patients and propensity-matched baseline cohorts. 778 patients had a viral load that was either not detected by RT-PCR (N = 596) or detectable, but below the limit of quantification (N = 182) at T0. Detectable viremia, lower T0 CD4 count, decreased age, and having detectable or unknown VL within a year prior to T0 were each associated with viral rebound to >50, >200 and >400 copies/mL. Overall failure rates were low and <5.5% of all patients had confirmed VL >1000 copies/mL. A majority of patients with rebound >200 copies/mL subsequently re-suppressed (28 of 53). A detectable VL <48 copies/mL was independently and significantly associated with subsequent viral rebound, and is cause for clinical concern.
authors.affiliation: Division of Infectious Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America. thenrich@partners.org
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Henrich
authors.forename: Brian R
authors.initials: BR
authors.lastname: Wood
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Kuritzkes
mesh_terms: D000367:Age Factors; D000998:Antiviral Agents / Q000627:therapeutic use*; D015496:CD4-Positive T-Lymphocytes / Q000821:virology; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology*; D015497:HIV-1 / Q000254:growth & development* / Q000302:isolation & purification; D006801:Humans; D016016:Proportional Hazards Models; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012737:Sex Factors; D018709:Statistics, Nonparametric; D019562:Viral Load
chemical_list: D000998:Antiviral Agents