title: Comparison of HIV-1 genotypic resistance test interpretation systems in predicting virological outcomes over time.
abstract: BACKGROUND
  Several decision support systems have been developed to interpret HIV-1 drug resistance genotyping results. This study compares the ability of the most commonly used systems (ANRS, Rega, and Stanford's HIVdb) to predict virological outcome at 12, 24, and 48 weeks.
  
  
  RESULTS
  Included were 3763 treatment-change episodes (TCEs) for which a HIV-1 genotype was available at the time of changing treatment with at least one follow-up viral load measurement. Genotypic susceptibility scores for the active regimens were calculated using scores defined by each interpretation system. Using logistic regression, we determined the association between the genotypic susceptibility score and proportion of TCEs having an undetectable viral load (<50 copies/ml) at 12 (8-16) weeks (2152 TCEs), 24 (16-32) weeks (2570 TCEs), and 48 (44-52) weeks (1083 TCEs). The Area under the ROC curve was calculated using a 10-fold cross-validation to compare the different interpretation systems regarding the sensitivity and specificity for predicting undetectable viral load. The mean genotypic susceptibility score of the systems was slightly smaller for HIVdb, with 1.92+/-1.17, compared to Rega and ANRS, with 2.22+/-1.09 and 2.23+/-1.05, respectively. However, similar odds ratio's were found for the association between each-unit increase in genotypic susceptibility score and undetectable viral load at week 12; 1.6 [95% confidence interval 1.5-1.7] for HIVdb, 1.7 [1.5-1.8] for ANRS, and 1.7 [1.9-1.6] for Rega. Odds ratio's increased over time, but remained comparable (odds ratio's ranging between 1.9-2.1 at 24 weeks and 1.9-2.2 at 48 weeks). The Area under the curve of the ROC did not differ between the systems at all time points; p = 0.60 at week 12, p = 0.71 at week 24, and p = 0.97 at week 48.
  
  
  CONCLUSIONS
  Three commonly used HIV drug resistance interpretation systems ANRS, Rega and HIVdb predict virological response at 12, 24, and 48 weeks, after change of treatment to the same extent.
authors.affiliation: Virology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors.forename: Dineke
authors.initials: D
authors.lastname: Frentz
authors.forename: Charles A B
authors.initials: CA
authors.lastname: Boucher
authors.forename: Matthias
authors.initials: M
authors.lastname: Assel
authors.forename: Andrea
authors.initials: A
authors.lastname: De Luca
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Fabbiani
authors.forename: Francesca
authors.initials: F
authors.lastname: Incardona
authors.forename: Pieter
authors.initials: P
authors.lastname: Libin
authors.forename: Nino
authors.initials: N
authors.lastname: Manca
authors.forename: Viktor
authors.initials: V
authors.lastname: Müller
authors.forename: Breanndán
authors.initials: B
authors.lastname: O Nualláin
authors.forename: Roger
authors.initials: R
authors.lastname: Paredes
authors.forename: Mattia
authors.initials: M
authors.lastname: Prosperi
authors.forename: Eugenia
authors.initials: E
authors.lastname: Quiros-Roldan
authors.forename: Lidia
authors.initials: L
authors.lastname: Ruiz
authors.forename: Peter M A
authors.initials: PM
authors.lastname: Sloot
authors.forename: Carlo
authors.initials: C
authors.lastname: Torti
authors.forename: Anne-Mieke
authors.initials: AM
authors.lastname: Vandamme
authors.forename: Kristel
authors.initials: K
authors.lastname: Van Laethem
authors.forename: Maurizio
authors.initials: M
authors.lastname: Zazzi
authors.forename: David A M C
authors.initials: DA
authors.lastname: van de Vijver
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D019562:Viral Load; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents