title: The impact of adherence on CD4 cell count responses among HIV-infected patients.
abstract: BACKGROUND
  There have been concerns that irreversible immune damage may result if highly active antiretroviral therapy (HAART) is initiated after the CD4 cell count declines to below 350 cells/microL; however, the role of antiretroviral adherence on CD4 cell count responses has not been well evaluated.
  
  
  METHODS
  We evaluated CD4 cell count responses of 1522 antiretroviral-naive patients initiating HAART who were stratified by baseline CD4 cell count (<50, 50-199, and >or=200 cells/microL) and adherence.
  
  
  RESULTS
  Among patients starting HAART with <50 cells/microL, during the fifth 15-week period after the initiation of HAART, absolute CD4 cell counts were 200 cells/microL (interquartile range [IQR]: 130-290) for adherent patients versus 60 cells/microL (IQR: 10-130) for nonadherent patients. Similarly, among patients starting HAART with 50 to 199 cells/microL, during the fifth 15-week period after the initiation of HAART, absolute CD4 cell counts were 300 cells/microL (IQR: 180-390) versus 125 cells/microL (IQR: 40-210) for nonadherent patients. In Cox regression analyses, adherence was the strongest independent predictor of the time to a gain of >or=50 cells/microL from baseline (relative hazard [RH] = 2.88, 95% confidence interval [CI]: 2.46-3.37). Among patients with baseline CD4 cell counts <200 cells/microL, adherence was the strongest independent predictor of the time to a CD4 cell count >200 cells/microL (RH = 4.85, 95% CI: 3.15-7.47).
  
  
  CONCLUSIONS
  These data demonstrate that substantial CD4 gains are possible among highly advanced adherent patients and should contribute to the ongoing debate over the optimal time to initiate HAART.
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Evan
authors.initials: E
authors.lastname: Wood
authors.forename: Robert S
authors.initials: RS
authors.lastname: Hogg
authors.forename: Benita
authors.initials: B
authors.lastname: Yip
authors.forename: P Richard
authors.initials: PR
authors.lastname: Harrigan
authors.forename: Michael V
authors.initials: MV
authors.lastname: O'Shaughnessy
authors.forename: Julio S G
authors.initials: JS
authors.lastname: Montaner
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology; D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D002170:Canada; D016001:Confidence Intervals; D005260:Female; D006678:HIV / Q000235:genetics / Q000302:isolation & purification; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015166:Monitoring, Immunologic; D010349:Patient Compliance; D012367:RNA, Viral / Q000097:blood; D012044:Regression Analysis; D015819:Substance Abuse, Intravenous / Q000453:epidemiology
chemical_list: D012367:RNA, Viral