title: Adherence to antiretroviral therapy and CD4 T-cell count responses among HIV-infected injection drug users.
abstract: OBJECTIVE
  To evaluate the time to CD4 cell count response (> or = 50 cells/mm3) among patients initiating highly active antiretroviral therapy (HAART) with and without a history of injection drug use, and to examine the potential role of non-adherence to HAART on differential CD4 responses.
  
  
  METHODS
  Population-based analysis of treatment-naive patients initiating HAART during the period 1 August 1996 to 31 July 2000 and who were followed until 31 March 2002. Patients were stratified based on 95% adherence and history of injection drug use, and Kaplan-Meier methods and Cox regression were used to evaluate CD4 response rates and factors associated with CD4 responses.
  
  
  RESULTS
  Overall, the CD4 cell count response rate was slower among injection drug users in Kaplan-Meier analyses (log-rank: P<0.05). However, no differences existed when the analyses were restricted to adherent patients (log-rank: P=0.349). Similarly, the differences in the time to CD4 cell count response observed in univariate Cox regression analyses for patients with a history of injection drug use [relative hazard: 0.85 (95% CI: 0.75-0.97)] diminished after adjustment for adherence [adjusted relative hazard: 1.02 (95% CI: 0.89-1.16)].
  
  
  CONCLUSIONS
  These data demonstrate the importance of adherence on CD4 cell count responses and highlight the need for interventions to improve antiretroviral adherence among injection drug user.
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St Paul's Hospital, Vancouver, BC, Canada. ewood@hivnet.ubc.ca
authors.forename: Evan
authors.initials: E
authors.lastname: Wood
authors.forename: Julio S G
authors.initials: JS
authors.lastname: Montaner
authors.forename: Benita
authors.initials: B
authors.lastname: Yip
authors.forename: Mark W
authors.initials: MW
authors.lastname: Tyndall
authors.forename: Martin T
authors.initials: MT
authors.lastname: Schechter
authors.forename: Michael V
authors.initials: MV
authors.lastname: O'Shaughnessy
authors.forename: Robert S
authors.initials: RS
authors.lastname: Hogg
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology*; D006801:Humans; D008297:Male; D010349:Patient Compliance; D015819:Substance Abuse, Intravenous / Q000150:complications*