title: A significant reduction in the frequency of HIV-1 drug resistance in Québec from 2001 to 2011 is associated with a decrease in the monitored viral load.
abstract: BACKGROUND
  HIV drug resistance represents a major threat for effective treatment. We assessed the trends in the frequency of drug resistance mutations and the monitored viral load (VL) in treatment-naïve (TN) and treatment-experienced (TE) individuals infected with HIV-1 in Québec, Canada, between 2001 and 2011.
  
  
  RESULTS
  Resistance data were obtained from 4,105 and 5,086 genotypic tests performed on TN and TE patients, respectively. Concomitantly, 274,161 VL tests were carried out in the Province. Changes over time in drug resistance frequency and in different categories of VL were assessed using univariate logistic regression. Multiple logistic regression was used to evaluate associations between the rates of certain mutations and antiretroviral prescriptions. From 2001 to 2011, the proportion of undetectable VL test results continually increased, from 42.1% to 75.9%, while a significant decrease in the frequency of resistance mutations associated with protease inhibitors [PI (from 54% to 16%)], nucleoside [NRTI (from 78% to 37%) and non-nucleoside reverse transcriptase inhibitors [NNRTI (from 44% to 31%)] was observed in TE patients. In TN individuals, the overall frequency of transmitted drug resistance was 13.1%. A multiple logistic regression analysis indicated that the introduction of co-formulated emtricitabine/tenofovir or emtricitabine/tenofovir/efavirenz was positively associated with the decrease of the frequency of the M184I/V mutations observed overtime (p = 0.0004).
  
  
  CONCLUSIONS
  We observed a significant decrease in the frequency of drug resistance mutations in TE patients, concomitant with a decrease in the proportion of patients with detectable viremia. These findings may be related to both the increased potencies and adherence to therapy associated with newer antiretroviral regimens. Nevertheless, our data demonstrate that broad use of antiretrovirals does not increase the level of circulating drug resistant variants.
authors.affiliation: Laboratoire de santé publique du Québec/Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada; Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Hugues
authors.initials: H
authors.lastname: Charest
authors.affiliation: Laboratoire de santé publique du Québec/Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada; Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Florence
authors.initials: F
authors.lastname: Doualla-Bell
authors.affiliation: Laboratoire de santé publique du Québec/Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada.
authors.forename: Régis
authors.initials: R
authors.lastname: Cantin
authors.affiliation: Laboratoire de santé publique du Québec/Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada.
authors.forename: Donald G
authors.initials: DG
authors.lastname: Murphy
authors.affiliation: Laboratoire de santé publique du Québec/Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: Lemieux
authors.affiliation: McGill AIDS Center, Lady Davis Institute, Jewish General Hospital, McGill University, Montréal, Québec, Canada.
authors.forename: Bluma
authors.initials: B
authors.lastname: Brenner
authors.affiliation: Centre hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Hardy
authors.affiliation: McGill AIDS Center, Lady Davis Institute, Jewish General Hospital, McGill University, Montréal, Québec, Canada.
authors.forename: Daniela
authors.initials: D
authors.lastname: Moisi
authors.affiliation: Laboratoire de santé publique du Québec/Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada; Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, Québec, Canada.
authors.forename: Ernest
authors.initials: E
authors.lastname: Lo
authors.affiliation: Clinique du Quartier Latin, Montréal, Québec, Canada.
authors.forename: Jean-Guy
authors.initials: JG
authors.lastname: Baril
authors.affiliation: McGill AIDS Center, Lady Davis Institute, Jewish General Hospital, McGill University, Montréal, Québec, Canada.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wainberg
authors.affiliation: Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, Québec, Canada; Centre hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada.
authors.forename: Michel
authors.initials: M
authors.lastname: Roger
authors.affiliation: Laboratoire de santé publique du Québec/Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada; Département de microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, Québec, Canada; Centre hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada.
authors.forename: Cécile
authors.initials: C
authors.lastname: Tremblay
mesh_terms: D019380:Anti-HIV Agents / Q000494:pharmacology; D024882:Drug Resistance, Viral / Q000235:genetics; D062665:Epidemiological Monitoring; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D006801:Humans; D009154:Mutation; D011792:Quebec / Q000453:epidemiology; D019562:Viral Load / Q000187:drug effects*
chemical_list: D019380:Anti-HIV Agents