title: HIV resistance testing and detected drug resistance in Europe.
abstract: OBJECTIVE
  To describe regional differences and trends in resistance testing among individuals experiencing virological failure and the prevalence of detected resistance among those individuals who had a genotypic resistance test done following virological failure.
  
  
  METHODS
  Multinational cohort study.
  
  
  METHODS
  Individuals in EuroSIDA with virological failure (>1 RNA measurement >500 on ART after >6 months on ART) after 1997 were included. Adjusted odds ratios (aORs) for resistance testing following virological failure and aORs for the detection of resistance among those who had a test were calculated using logistic regression with generalized estimating equations.
  
  
  RESULTS
  Compared to 74.2% of ART-experienced individuals in 1997, only 5.1% showed evidence of virological failure in 2012. The odds of resistance testing declined after 2004 (global P < 0.001). Resistance was detected in 77.9% of the tests, NRTI resistance being most common (70.3%), followed by NNRTI (51.6%) and protease inhibitor (46.1%) resistance. The odds of detecting resistance were lower in tests done in 1997-1998, 1999-2000 and 2009-2010, compared to those carried out in 2003-2004 (global P < 0.001). Resistance testing was less common in Eastern Europe [aOR 0.72, 95% confidence interval (CI) 0.55-0.94] compared to Southern Europe, whereas the detection of resistance given that a test was done was less common in Northern (aOR 0.29, 95% CI 0.21-0.39) and Central Eastern (aOR 0.47, 95% CI 0.29-0.76) Europe, compared to Southern Europe.
  
  
  CONCLUSIONS
  Despite a concurrent decline in virological failure and testing, drug resistance was commonly detected. This suggests a selective approach to resistance testing. The regional differences identified indicate that policy aiming to minimize the emergence of resistance is of particular relevance in some European regions, notably in the countries in Eastern Europe.
authors.affiliation: aDepartment of Infection and Population Health, University College London, London, UK bFundacions irsiCaixa i Lluita contra la SIDA, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Catalonia, Spain cDivision of Infectious Diseases and Hospital Epidemiology, Departments of Medicine and Clinical Research, University Hospital Basel, Switzerland dUniversitäts Klinik, Bonn, Germany eDepartment of Infectious Diseases, Third Faculty of Medicine, Charles University and Hospital Na Bulovce in Prague, Czech Republic fClinic for Infectious Diseases, University Medical Centre, Ljubljana, Slovenia gService des Maladies Infectieuses, APHP, Hôpital St Antoine and INSERM, UMR_S1136, Paris, France hState Agency Infectology Center of Latvia, Riga, Latvia iRigshospitalet, University of Copenhagen, CHIP at Department of Infectious Diseases, Copenhagen, Denmark.
authors.forename: Anna
authors.initials: A
authors.lastname: Schultze
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Phillips
authors.forename: Roger
authors.initials: R
authors.lastname: Paredes
authors.forename: Manuel
authors.initials: M
authors.lastname: Battegay
authors.forename: Jürgen K
authors.initials: JK
authors.lastname: Rockstroh
authors.forename: Ladislav
authors.initials: L
authors.lastname: Machala
authors.forename: Janez
authors.initials: J
authors.lastname: Tomazic
authors.forename: Pierre M
authors.initials: PM
authors.lastname: Girard
authors.forename: Inga
authors.initials: I
authors.lastname: Januskevica
authors.forename: Kamilla
authors.initials: K
authors.lastname: Gronborg-Laut
authors.forename: Jens D
authors.initials: JD
authors.lastname: Lundgren
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cozzi-Lepri
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D024882:Drug Resistance, Viral / Q000235:genetics*; D005060:Europe; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy*; D017320:HIV Protease Inhibitors / Q000627:therapeutic use*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use*; D017211:Treatment Failure; D019562:Viral Load / Q000187:drug effects
chemical_list: D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors