title: Patterns, predictors, and consequences of initial regimen type among HIV-infected women receiving highly active antiretroviral therapy.
abstract: BACKGROUND
  It is important to elucidate differences among initial highly active antiretroviral therapy (HAART) regimen types in comparative studies of therapy effectiveness. We aimed to identify predictors of initiation with different HAART regimen types and the effect of initial regimen type on switching and immunologic response to therapy--controlling for those predictors--among human immunodeficiency virus (HIV)-infected women in the United States.
  
  
  METHODS
  Participants in the Women's Interagency HIV Study underwent semiannual interview, venipuncture, and clinical examination. Those beginning with protease inhibitor-based, nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based, or triple-nucleoside reverse-transcriptase inhibitor (NRTI)-based HAART during April 1996-March 2005 were eligible for analysis. Predictors of initial regimen type were assessed with polytomous logistic regression. Correlates of switching were assessed with discrete-time proportional hazards models, and immunologic response to therapy was assessed with linear regression.
  
  
  RESULTS
  Among 1555 HAART initiators, CD4(+) lymphocyte count and HIV load were significant predictors of initial regimen type during 1996-2002; only sociodemographic predictors were significant during 2002-2005. Initial regimen type was not a significant predictor of subsequent regimen switching. Compared with those whose initial treatment was protease inhibitor-based HAART, those who began with triple-NRTI-based regimens had significantly lower CD4(+) cell counts at 1 year (P=.006) and 2 years (P=.004) after initiation; NNRTI initiators had lower CD4(+) cell counts after 2 years (P=.05).
  
  
  CONCLUSIONS
  We demonstrate that predictors of initial regimen type among women in the United States have been changing over time. Protease inhibitor initiators had significantly higher CD4(+) cell counts than did NNRTI or triple-NRTI initiators up to 2 years after HAART initiation. Adjustment for biological predictors of initial regimen is important to avoid confounding in the study of treatment effectiveness.
authors.affiliation: Johns Hopkins Bloomberg School of Public Health, Department of Epidemiology, Baltimore, Maryland 21205, USA. egolub@jhsph.edu
authors.forename: Elizabeth T
authors.initials: ET
authors.lastname: Golub
authors.forename: Lorie
authors.initials: L
authors.lastname: Benning
authors.forename: Anjali
authors.initials: A
authors.lastname: Sharma
authors.forename: Monica
authors.initials: M
authors.lastname: Gandhi
authors.forename: Mardge H
authors.initials: MH
authors.lastname: Cohen
authors.forename: Mary
authors.initials: M
authors.lastname: Young
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Gange
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D018450:Disease Progression; D004334:Drug Administration Schedule; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology / Q000821:virology; D017320:HIV Protease Inhibitors / Q000008:administration & dosage*; D006801:Humans; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage*; D012959:Socioeconomic Factors; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: D017320:HIV Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors