title: Patterns and predictors of the use of different antiretroviral drug regimens at treatment initiation in the UK.
abstract: BACKGROUND
  We describe the patterns of antiretroviral drug use at treatment initiation from 1996 to 2005 in a large UK multicentre cohort.
  
  
  METHODS
  We examined trends over time and across 10 clinical sites in stage of disease and type of antiretroviral therapy (ART). Multivariable regression was used to identify factors associated with the CD4 cell count at ART initiation, and with the choice of a protease inhibitor (PI) over a nonnucleoside reverse transcriptase inhibitor (NNRTI), and use of nevirapine over efavirenz.
  
  
  RESULTS
  A total of 14 252 patients initiated ART, of whom 54% had a CD4 count <200 cells/microL. The most important predictors of starting ART at a lower CD4 cell count were being male, nonwhite, and heterosexual or an injecting drug user (P<0.0001). Among those starting ART, the use of highly active ART increased from 23% in 1996 to >96% from 2000 onwards. There were differences over time and across the clinics in the use of PIs vs. NNRTIs, in the choice of specific PIs, NNRTIs and nucleoside reverse transcriptase inhibitor (NRTI) backbone, and in the rate at which prescribing practices changed.
  
  
  CONCLUSIONS
  Clinic site and calendar year were important determinants of choice of drug at ART initiation, whereas clinical and demographic characteristics were more important in influencing the CD4 cell count at initiation of ART.
authors.affiliation: Department of HIV/GU Medicine, Kings College London School of Medicine at Guy's, London, UK. philippa.easterbrook@kcl.ac.uk
authors.forename: P J
authors.initials: PJ
authors.lastname: Easterbrook
authors.forename: A N
authors.initials: AN
authors.lastname: Phillips
authors.forename: T
authors.initials: T
authors.lastname: Hill
authors.forename: R
authors.initials: R
authors.lastname: Matthias
authors.forename: M
authors.initials: M
authors.lastname: Fisher
authors.forename: B
authors.initials: B
authors.lastname: Gazzard
authors.forename: R
authors.initials: R
authors.lastname: Gilson
authors.forename: G
authors.initials: G
authors.lastname: Scullard
authors.forename: M
authors.initials: M
authors.lastname: Johnson
authors.forename: D T
authors.initials: DT
authors.lastname: Dunn
authors.forename: C
authors.initials: C
authors.lastname: Orkin
authors.forename: J
authors.initials: J
authors.lastname: Anderson
authors.forename: A
authors.initials: A
authors.lastname: Schwenk
authors.forename: C
authors.initials: C
authors.lastname: Leen
authors.forename: C A
authors.initials: CA
authors.lastname: Sabin
mesh_terms: D000328:Adult; D000480:Alkynes; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods*; D048588:Benzoxazines / Q000008:administration & dosage; D018791:CD4 Lymphocyte Count; D003521:Cyclopropanes; D004334:Drug Administration Schedule; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008297:Male; D019829:Nevirapine / Q000008:administration & dosage; D010044:Outpatient Clinics, Hospital; D010349:Patient Compliance; D017410:Practice Guidelines as Topic; D010818:Practice Patterns, Physicians'; D011480:Protease Inhibitors / Q000008:administration & dosage*; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage*; D013997:Time Factors; D006113:United Kingdom
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D011480:Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors; D019829:Nevirapine; C098320:efavirenz