title: The incidence of multidrug and full class resistance in HIV-1 infected patients is decreasing over time (2001-2006) in Portugal.
abstract: Despite improvements in HIV treatment, the prevalence of multidrug resistance and full class resistance is still reported to be increasing. However, to investigate whether current treatment strategies are still selecting for multidrug and full class resistance, the incidence, instead of the prevalence, is more informative. Temporal trends in multidrug resistance (MDR defined as at most 1 drug fully susceptible) and full class resistance (FCR defined as no drug in this class fully susceptible) in Portugal based on 3394 viral isolates genotyped from 2000 to 2006 were examined using the Rega 6.4.1 interpretation system. From July 2001 to July 2006 there was a significant decreasing trend of MDR with 5.7%, 5.2%, 3.8%, 3.4% and 2.7% for the consecutive years (P = 0.003). Multivariate analysis showed that for every consecutive year the odds of having a new MDR case decreased with 20% (P = 0.003). Furthermore, a decline was observed for NRTI- and PI-FCR (both P < 0.001), whereas for NNRTI-FCR a parabolic trend over time was seen (P < 0.001), with a maximum incidence in 2003-'04. Similar trends were obtained when scoring resistance for only one drug within a class or by using another interpretation system. In conclusion, the incidence of multidrug and full class resistance is decreasing over time in Portugal, with the exception of NNRTI full class resistance which showed an initial rise, but subsequently also a decline. This is most probably reflecting the changing drug prescription, the increasing efficiency of HAART and the improved management of HIV drug resistance. This work was presented in part at the Eighth International Congress on Drug Therapy in HIV Infection, Glasgow (UK), 12-16 November 2006 (PL5.5); and at the Fifth European HIV Drug Resistance Workshop, Cascais (Portugal), 28-30 March 2007 (Abstract 1).
authors.affiliation: Rega Institute, Katholieke Universiteit Leuven, Leuven, Belgium. jurgen.vercauteren@uz.kuleuven.ac.be
authors.forename: Jurgen
authors.initials: J
authors.lastname: Vercauteren
authors.forename: Koen
authors.initials: K
authors.lastname: Deforche
authors.forename: Kristof
authors.initials: K
authors.lastname: Theys
authors.forename: Michiel
authors.initials: M
authors.lastname: Debruyne
authors.forename: Luis Miguel
authors.initials: LM
authors.lastname: Duque
authors.forename: Susana
authors.initials: S
authors.lastname: Peres
authors.forename: Ana Patricia
authors.initials: AP
authors.lastname: Carvalho
authors.forename: Kamal
authors.initials: K
authors.lastname: Mansinho
authors.forename: Anne-Mieke
authors.initials: AM
authors.lastname: Vandamme
authors.forename: Ricardo
authors.initials: R
authors.lastname: Camacho
mesh_terms: D019380:Anti-HIV Agents / Q000494:pharmacology* / Q000627:therapeutic use; D023241:Antiretroviral Therapy, Highly Active; D024921:Drug Resistance, Multiple, Viral; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology / Q000517:prevention & control* / Q000821:virology*; D015497:HIV-1 / Q000145:classification / Q000187:drug effects*; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D011174:Portugal / Q000453:epidemiology
chemical_list: D019380:Anti-HIV Agents