title: Does discordancy between the CD4 count and CD4 percentage in HIV-positive individuals influence outcomes on highly active antiretroviral therapy?
abstract: BACKGROUND
  The CD4 count and CD4 percentage (CD4%) are both strong predictors of clinical disease progression in human immunodeficiency virus (HIV). Although individuals may show discordancy between their CD4 count and CD4%, the clinical relevance of this is unclear.
  
  
  METHODS
  Discordancy was defined where the CD4% was ≤10th percentile for a selected CD4 count range (referred to as low discordancy), within the central 80% range (concordant), or ≥90th percentile (high discordancy). Regression methods identified factors associated with low and high discordancy in untreated individuals and assessed the impact of discordancy on treatment responses to highly active antiretroviral therapy (HAART).
  
  
  RESULTS
  High discordancy was associated with female sex, low viral load, and white ethnicity; low discordancy was associated with black or nonwhite ethnicity, older age, and injection drug use. Clinical event rates were higher in individuals with high discordancy starting HAART, but there was no association with subsequent HIV progression by 6 months after starting HAART. CD4 count increases remained lower, by 20 cells/mm(3), in individuals with low discordancy, and higher, by 27 cells/mm(3), in those with high discordancy.
  
  
  CONCLUSIONS
  Overall discrepancies between the CD4/CD4% are small, confirming the use of absolute CD4 counts as a monitoring tool.
authors.affiliation: North Bristol NHS Trust, Bristol, United Kingdom. mark.gompels@nbt.nhs.uk
authors.forename: Mark
authors.initials: M
authors.lastname: Gompels
authors.forename: David T
authors.initials: DT
authors.lastname: Dunn
authors.forename: Andrew
authors.initials: A
authors.lastname: Phillips
authors.forename: Debbie
authors.initials: D
authors.lastname: Dooley
authors.forename: Andrew
authors.initials: A
authors.lastname: De Burgh Thomas
authors.forename: Jane
authors.initials: J
authors.lastname: Anderson
authors.forename: Frank
authors.initials: F
authors.lastname: Post
authors.forename: Deenan
authors.initials: D
authors.lastname: Pillay
authors.forename: Brian
authors.initials: B
authors.lastname: Gazzard
authors.forename: Teresa
authors.initials: T
authors.lastname: Hill
authors.forename: Margaret
authors.initials: M
authors.lastname: Johnson
authors.forename: Richard
authors.initials: R
authors.lastname: Gilson
authors.forename: Loveleen
authors.initials: L
authors.lastname: Bansi
authors.forename: Philippa
authors.initials: P
authors.lastname: Easterbrook
authors.forename: Martin
authors.initials: M
authors.lastname: Fisher
authors.forename: John
authors.initials: J
authors.lastname: Walsh
authors.forename: Chloe
authors.initials: C
authors.lastname: Orkin
authors.forename: Jonathan
authors.initials: J
authors.lastname: Ainsworth
authors.forename: Clifford
authors.initials: C
authors.lastname: Leen
authors.forename: Caroline
authors.initials: C
authors.lastname: Sabin
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D019380:Anti-HIV Agents