title: Transient detectable viremia and the risk of viral rebound in patients from the Swiss HIV Cohort Study.
abstract: BACKGROUND
  Temporary increases in plasma HIV RNA ('blips') are common in HIV patients on combination antiretroviral therapy (cART). Blips above 500 copies/mL have been associated with subsequent viral rebound. It is not clear if this relationship still holds when measurements are made using newer more sensitive assays.
  
  
  METHODS
  We selected antiretroviral-naive patients that then recorded one or more episodes of viral suppression on cART with HIV RNA measurements made using more sensitive assays (lower limit of detection below 50 copies/ml). We estimated the association in these episodes between blip magnitude and the time to viral rebound.
  
  
  RESULTS
  Four thousand ninety-four patients recorded a first episode of viral suppression on cART using more sensitive assays; 1672 patients recorded at least one subsequent suppression episode. Most suppression episodes (87 %) were recorded with TaqMan version 1 or 2 assays. Of the 2035 blips recorded, 84 %, 12 % and 4 % were of low (50-199 copies/mL), medium (200-499 copies/mL) and high (500-999 copies/mL) magnitude respectively. The risk of viral rebound increased as blip magnitude increased with hazard ratios of 1.20 (95 % CI 0.89-1.61), 1.42 (95 % CI 0.96-2.19) and 1.93 (95 % CI 1.24-3.01) for low, medium and high magnitude blips respectively; an increase of hazard ratio 1.09 (95 % CI 1.03 to 1.15) per 100 copies/mL of HIV RNA.
  
  
  CONCLUSIONS
  With the more sensitive assays now commonly used for monitoring patients, blips above 200 copies/mL are increasingly likely to lead to viral rebound and should prompt a discussion about adherence.
authors.affiliation: Basel Institute for Clinical Epidemiology and Biostatistics, University Hospital Basel, Basel, Switzerland. James.Young@usb.ch.
authors.forename: Jim
authors.initials: J
authors.lastname: Young
authors.affiliation: Institute of Social and Preventive Medicine, University of Lausanne, Lausanne, Switzerland. Martin.Rickenbach@chuv.ch.
authors.forename: Martin
authors.initials: M
authors.lastname: Rickenbach
authors.affiliation: Division of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland. Alexandra.Calmy@hcuge.ch.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Calmy
authors.affiliation: Division of Infectious Diseases, Regional Hospital of Lugano, Lugano, Switzerland. Enos.Bernasconi@eoc.ch.
authors.forename: Enos
authors.initials: E
authors.lastname: Bernasconi
authors.affiliation: Department of Infectious Diseases, Bern University Hospital and University of Bern, Bern, Switzerland. Cornelia.Staehelin@insel.ch.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Staehelin
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, Cantonal Hospital St. Gallen, St Gallen, Switzerland. Patrick.Schmid@kssg.ch.
authors.forename: Patrick
authors.initials: P
authors.lastname: Schmid
authors.affiliation: Division of Infectious Diseases, University Hospital Lausanne, Lausanne, Switzerland. Matthias.Cavassini@chuv.ch.
authors.forename: Matthias
authors.initials: M
authors.lastname: Cavassini
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland. Manuel.Battegay@usb.ch.
authors.forename: Manuel
authors.initials: M
authors.lastname: Battegay
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital and University of Zürich, Zurich, Switzerland. Huldrych.Guenthard@usz.ch.
authors.forename: Huldrych F
authors.initials: HF
authors.lastname: Günthard
authors.affiliation: Basel Institute for Clinical Epidemiology and Biostatistics, University Hospital Basel, Basel, Switzerland. Heiner.Bucher@usb.ch.|Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland. Heiner.Bucher@usb.ch.
authors.forename: Heiner C
authors.initials: HC
authors.lastname: Bucher
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012367:RNA, Viral / Q000097:blood; D012306:Risk; D019562:Viral Load; D014766:Viremia / Q000175:diagnosis* / Q000821:virology
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral