title: Virologic and immunologic response to HAART, by age and regimen class.
abstract: OBJECTIVE
  To determine the impact of age and initial HAART regimen class on virologic and immunologic response within 24 months after initiation.
  
  
  METHODS
  Pooled analysis of data from 19 prospective cohort studies in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD).
  
  
  METHODS
  Twelve thousand, one hundred and ninety-six antiretroviral-naive adults who initiated HAART between 1998 and 2008 using a boosted protease inhibitor-based regimen or a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen were included in our study. Discrete time-to-event models estimated adjusted hazard odds ratios (aHOR) and 95% confidence intervals (CIs) for suppressed viral load (≤500 copies/ml) and, separately, at least 100 cells/μl increase in CD4 cell count. Truncated, stabilized inverse probability weights accounted for selection biases from discontinuation of initial regimen class.
  
  
  RESULTS
  Among 12 196 eligible participants (mean age = 42 years), 50% changed regimen classes after initiation (57 and 48% of whom initiated protease inhibitor and NNRTI-based regimens, respectively). Mean CD4 cell count at initiation was similar by age. Virologic response to treatment was less likely in those initiating using a boosted protease inhibitor [aHOR = 0.77 (0.73, 0.82)], regardless of age. Immunologic response decreased with increasing age [18-<30: ref; 30-<40: aHOR = 0.92 (0.85, 1.00); 40-<50: aHOR = 0.85 (0.78, 0.92); 50-<60: aHOR = 0.82 (0.74, 0.90); ≥60: aHOR = 0.74 (0.65, 0.85)], regardless of initial regimen.
  
  
  CONCLUSIONS
  We found no evidence of an interaction between age and initial antiretroviral regimen on virologic or immunologic response to HAART; however, decreased immunologic response with increasing age may have implications for age-specific when-to-start guidelines.
authors.affiliation: Johns Hopkins University, Baltimore, Maryland 21287, USA.
authors.forename: Keri N
authors.initials: KN
authors.lastname: Althoff
authors.forename: Amy C
authors.initials: AC
authors.lastname: Justice
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Gange
authors.forename: Steven G
authors.initials: SG
authors.lastname: Deeks
authors.forename: Michael S
authors.initials: MS
authors.lastname: Saag
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Silverberg
authors.forename: M John
authors.initials: MJ
authors.lastname: Gill
authors.forename: Bryan
authors.initials: B
authors.lastname: Lau
authors.forename: Sonia
authors.initials: S
authors.lastname: Napravnik
authors.forename: Ellen
authors.initials: E
authors.lastname: Tedaldi
authors.forename: Marina B
authors.initials: MB
authors.lastname: Klein
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Gebo
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology / Q000821:virology; D015497:HIV-1; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000276:immunology*; D019562:Viral Load; D055815:Young Adult
chemical_list: D012367:RNA, Viral