title: Time trends in primary resistance to HIV drugs in the United Kingdom: multicentre observational study.
abstract: OBJECTIVE
  To examine whether the level of primary resistance to HIV drugs is increasing in the United Kingdom.
  
  
  METHODS
  Multicentre observational study.
  
  
  METHODS
  All virology laboratories in the United Kingdom carrying out tests for HIV resistance as part of routine clinical care.
  
  
  METHODS
  2357 people infected with HIV who were tested for resistance before receiving antiretroviral therapy.
  
  
  METHODS
  Prevalence of drug resistance on basis of the Stanford genotypic interpretation system.
  
  
  RESULTS
  Over the study period (February 1996 to May 2003), 335 (14.2%, 95% confidence interval 12.8% to 15.7%) samples had mutations that conferred resistance to one or more antiretroviral drugs (9.3% high level resistance, 5.9% medium level resistance). The prevalence of primary resistance has increased markedly over time, although patterns are specific to drug class; the largest increase was for non-nucleoside reverse transcriptase inhibitors. In 2002-3, the prevalence of resistance to any antiretroviral drug to nucleoside or nucleotide reverse transcriptase inhibitors, to non-nucleoside reverse transcriptase inhibitors, or to protease inhibitors was 19.2% (15.7% to 23.2%), 12.4% (9.5% to 15.9%), 8.1% (5.8% to 11.1%), and 6.6% (4.4% to 9.3%), respectively. The risk of primary resistance was only weakly related to most demographic and clinical factors, including ethnicity and viral subtype.
  
  
  CONCLUSIONS
  The United Kingdom has one of the highest reported rates of primary resistance to HIV drugs worldwide. Prevalence seems still to be increasing and is high in all demographic subgroups.
authors.forename: Patricia
authors.initials: P
authors.lastname: Cane
authors.forename: Ian
authors.initials: I
authors.lastname: Chrystie
authors.forename: David
authors.initials: D
authors.lastname: Dunn
authors.forename: Barry
authors.initials: B
authors.lastname: Evans
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Geretti
authors.forename: Hannah
authors.initials: H
authors.lastname: Green
authors.forename: Andrew
authors.initials: A
authors.lastname: Phillips
authors.forename: Deenan
authors.initials: D
authors.lastname: Pillay
authors.forename: Kholoud
authors.initials: K
authors.lastname: Porter
authors.forename: Anton
authors.initials: A
authors.lastname: Pozniak
authors.forename: Caroline
authors.initials: C
authors.lastname: Sabin
authors.forename: Erasmus
authors.initials: E
authors.lastname: Smit
authors.forename: Jonathan
authors.initials: J
authors.lastname: Weber
authors.forename: Mark
authors.initials: M
authors.lastname: Zuckerman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D024882:Drug Resistance, Viral / Q000235:genetics*; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000235:genetics; D006801:Humans; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D015995:Prevalence; D012044:Regression Analysis; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D019380:Anti-HIV Agents; D018894:Reverse Transcriptase Inhibitors