title: The prevalence of transmitted antiretroviral drug resistance in treatment-naïve patients and factors influencing first-line treatment regimen selection.
abstract: OBJECTIVE
  To estimate the prevalence of transmitted antiretroviral (ARV) drug resistance, and to assess whether resistance testing influences first-line ARV regimen selection.
  
  
  METHODS
  Data on patients' characteristics were collected through questionnaires. ARV drug resistance was tested by genotypic methods and defined by Quest-Stanford classification rule. Physicians reported the intended and actual treatments and the factors considered in treatment selection.
  
  
  RESULTS
  Two hundred and twenty-eight patients were included. The prevalence of ARV drug resistance was 12.1%, with 9.8% for non-nucleoside reverse transcriptase inhibitors (NNRTIs), 4.5% for nucleoside reverse transcriptase inhibitors and 1.8% for protease inhibitors (PIs). Pill burdens, dosing frequency and physicians' experience with regimens were the major factors considered in treatment selection. The intended and actual treatment differed for 73 and 44% of the patients with and without ARV drug resistance, respectively [odds ratio (95% confidence interval, CI)=3.6 (1.5-9.0), P=0.006]. NNRTI-based regimens were intended for 10 patients with resistance to NNRTIs; these patients were prescribed PI-based regimens after genotypic testing.
  
  
  CONCLUSIONS
  Transmitted ARV drug resistance was detected in 12.1% of treatment-naïve patients, with resistance to NNRTIs the most common. Resistance-testing results played a partial role in first-line treatment selection. However, resistance to NNRTIs pre-empted NNRTI use.
authors.affiliation: Outcomes Research and Management, Merck & Co. Inc., West Point, PA 19446, USA. han-yao_huang@merck.com
authors.forename: H-Y
authors.initials: HY
authors.lastname: Huang
authors.forename: E S
authors.initials: ES
authors.lastname: Daar
authors.forename: P E
authors.initials: PE
authors.lastname: Sax
authors.forename: B
authors.initials: B
authors.lastname: Young
authors.forename: P
authors.initials: P
authors.lastname: Cook
authors.forename: P
authors.initials: P
authors.lastname: Benson
authors.forename: C
authors.initials: C
authors.lastname: Cohen
authors.forename: A
authors.initials: A
authors.lastname: Scribner
authors.forename: H
authors.initials: H
authors.lastname: Hu
mesh_terms: D000328:Adult; D002985:Clinical Protocols; D003430:Cross-Sectional Studies; D004334:Drug Administration Schedule; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000235:genetics / Q000635:transmission; D016333:HIV Protease / Q000235:genetics*; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics; D006801:Humans; D008297:Male; D015995:Prevalence; D011480:Protease Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D011795:Surveys and Questionnaires; D017211:Treatment Failure
chemical_list: D011480:Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors; D016333:HIV Protease