title: Trends in detectable viral load by calendar year in the Australian HIV observational database.
abstract: BACKGROUND
  Recent papers have suggested that expanded combination antiretroviral treatment (cART) through lower viral load may be a strategy to reduce HIV transmission at a population level. We assessed calendar trends in detectable viral load in patients recruited to the Australian HIV Observational Database who were receiving cART.
  
  
  METHODS
  Patients were included in analyses if they had started cART (defined as three or more antiretrovirals) and had at least one viral load assessment after 1 January 1997. We analyzed detectable viral load (>400 copies/ml) in the first and second six months of each calendar year while receiving cART. Repeated measures logistic regression methods were used to account for within and between patient variability. Rates of detectable viral load were predicted allowing for patients lost to follow up.
  
  
  RESULTS
  Analyses were based on 2439 patients and 31,339 viral load assessments between 1 January 1997 and 31 March 2009. Observed detectable viral load in patients receiving cART declined to 5.3% in the first half of 2009. Predicted detectable viral load based on multivariate models, allowing for patient loss to follow up, also declined over time, but at higher levels, to 13.8% in 2009.
  
  
  CONCLUSIONS
  Predicted detectable viral load in Australian HIV Observational Database patients receiving cART declined over calendar time, albeit at higher levels than observed. However, over this period, HIV diagnoses and estimated HIV incidence increased in Australia.
authors.affiliation: National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, NSW, Australia. mlaw@nchecr.unsw.edu.au
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Law
authors.forename: Ian
authors.initials: I
authors.lastname: Woolley
authors.forename: David J
authors.initials: DJ
authors.lastname: Templeton
authors.forename: Norm
authors.initials: N
authors.lastname: Roth
authors.forename: John
authors.initials: J
authors.lastname: Chuah
authors.forename: Brian
authors.initials: B
authors.lastname: Mulhall
authors.forename: Peter
authors.initials: P
authors.lastname: Canavan
authors.forename: Hamish
authors.initials: H
authors.lastname: McManus
authors.forename: David A
authors.initials: DA
authors.lastname: Cooper
authors.forename: Kathy
authors.initials: K
authors.lastname: Petoumenos
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D001315:Australia / Q000453:epidemiology; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000821:virology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents