title: Declining risk of triple-class antiretroviral drug failure in Danish HIV-infected individuals.
abstract: OBJECTIVE
  To analyse the incidence, prevalence, and predictors for development of triple-class antiretroviral drug failure (TCF) in individuals infected with HIV.
  
  
  METHODS
  Population-based observational cohort study from 1 January 1995 to 31 December 2003, focusing on all 2722 recipients of highly active antiretroviral therapy (HAART) in Denmark.
  
  
  METHODS
  We used person-years analysis, Kaplan-Meier survival curves and Cox regression analysis. TCF was defined as a minimum of 120 days with viral load > 1000 copies/ml on treatment with each of the three major drug classes.
  
  
  RESULTS
  We observed 177 TCFs, yielding a crude incidence rate (IR) of 1.8 per 100 person-years [95% confidence interval (CI), 1.6-2.1]. Seven years after initiation of HAART, 17.2% (95% CI, 14.5-20.5) of antiretroviral (ART)-experienced patients, but only 7.0% (95% CI, 4.3-11.2) of ART-naive patients were estimated to have failed. After an initial rise, the IR from the third to the sixth year of HAART declined significantly for ART-experienced patients [incidence rate ratio (IRR), 0.80 per year (95% CI, 0.66-0.97); P = 0.022], and non-significantly for ART-naive patients [IRR, 0.79 per year (95% CI, 0.53-1.18); P = 0.255]. The IR for all patients being followed each year declined from 1997 to 2003 [IRR, 0.88 (95% CI, 0.81-0.96); P = 0.002]. The prevalence of TCF remained stable at less than 7% after 2000. Predictors of TCF at commencement of HAART were a CD4 cell count below 200, a previous AIDS-defining event, previous antiretroviral exposure, earlier year of HAART initiation, and young age.
  
  
  CONCLUSIONS
  The risk of TCF is declining in Denmark and the prevalence remains stable.
authors.affiliation: Odense University Hospital, and University of Southern Denmark, Odense, Denmark. nicolai.lohse@ouh.fyns-amt.dk
authors.forename: Nicolai
authors.initials: N
authors.lastname: Lohse
authors.forename: Niels
authors.initials: N
authors.lastname: Obel
authors.forename: Gitte
authors.initials: G
authors.lastname: Kronborg
authors.forename: Alex
authors.initials: A
authors.lastname: Laursen
authors.forename: Court
authors.initials: C
authors.lastname: Pedersen
authors.forename: Carsten S
authors.initials: CS
authors.lastname: Larsen
authors.forename: Birgit
authors.initials: B
authors.lastname: Kvinesdal
authors.forename: Henrik Toft
authors.initials: HT
authors.lastname: Sørensen
authors.forename: Jan
authors.initials: J
authors.lastname: Gerstoft
mesh_terms: D000328:Adult; D000367:Age Factors; D019380:Anti-HIV Agents / Q000627:therapeutic use; D044966:Anti-Retroviral Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D003718:Denmark; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000401:mortality / Q000821:virology; D015497:HIV-1; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012306:Risk; D015996:Survival Rate; D017211:Treatment Failure; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D044966:Anti-Retroviral Agents