Henrich, Timothy J.Wood, Brian R.Kuritzkes, Daniel2013-04-222012Henrich, Timothy J., Brian R. Wood, and Daniel R. Kuritzkes. 2012. Increased risk of virologic rebound in patients on antiviral therapy with a detectable HIV load <48 copies/ml. PLoS ONE 7(11): e50065.1932-6203http://nrs.harvard.edu/urn-3:HUL.InstRepos:10579220We 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.en-USBiologyMicrobiologyVirologyViral Transmission and InfectionViral LoadViral Disease DiagnosisViral ReplicationMedicineDiagnostic MedicineTest EvaluationInfectious DiseasesViral DiseasesHIVHIV clinical manifestationsHIV diagnosis and managementJournal Article2013-04-2210.1371/journal.pone.0050065