title: Magnitude of virologic blips is associated with a higher risk for virologic rebound in HIV-infected individuals: a recurrent events analysis.
abstract: BACKGROUND
  The importance of human immunodeficiency virus (HIV) blip magnitude on virologic rebound has been raised in clinical guidelines relating to viral load assays.
  
  
  METHODS
  Antiretroviral-naive individuals initiating combination antiretroviral therapy (cART) after 1 January 2000 and achieving virologic suppression were studied. Negative binomial models were used to identify blip correlates. Recurrent event models were used to determine the association between blips and rebound by incorporating multiple periods of virologic suppression per individual.
  
  
  RESULTS
  3550 participants (82% male; median age, 40 years) were included. In a multivariable negative binomial regression model, the Amplicor assay was associated with a lower blip rate than branched DNA (rate ratio, 0.69; P < .01), controlling for age, sex, region, baseline HIV-1 RNA and CD4 count, AIDS-defining illnesses, year of cART initiation, cART type, and HIV-1 RNA testing frequency. In a multivariable recurrent event model controlling for age, sex, intravenous drug use, cART start year, cART type, assay type, and HIV-1 RNA testing frequency, blips of 500-999 copies/mL were associated with virologic rebound (hazard ratio, 2.70; P = .002), whereas blips of 50-499 were not.
  
  
  CONCLUSIONS
  HIV-1 RNA assay was an important determinant of blip rates and should be considered in clinical guidelines. Blips ≥500 copies/mL were associated with increased rebound risk.
authors.affiliation: McMaster University, Hamilton, Canada.
authors.forename: J Troy
authors.initials: JT
authors.lastname: Grennan
authors.forename: Mona R
authors.initials: MR
authors.lastname: Loutfy
authors.forename: DeSheng
authors.initials: D
authors.lastname: Su
authors.forename: P Richard
authors.initials: PR
authors.lastname: Harrigan
authors.forename: Curtis
authors.initials: C
authors.lastname: Cooper
authors.forename: Marina
authors.initials: M
authors.lastname: Klein
authors.forename: Nima
authors.initials: N
authors.lastname: Machouf
authors.forename: Julio S G
authors.initials: JS
authors.lastname: Montaner
authors.forename: Sean
authors.initials: S
authors.lastname: Rourke
authors.forename: Christos
authors.initials: C
authors.lastname: Tsoukas
authors.forename: Bob
authors.initials: B
authors.lastname: Hogg
authors.forename: Janet
authors.initials: J
authors.lastname: Raboud
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000627:therapeutic use; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000821:virology*; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D012367:RNA, Viral / Q000097:blood; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral