title: Pretreatment HIV-1 drug resistance to first-line drugs: results from a baseline assessment of a large cohort initiating ART in Vietnam, 2009-10.
abstract: OBJECTIVE
  The objective of this study was to determine the prevalence and correlates of pretreatment drug resistance (PDR) to first-line antiretroviral drugs among people initiating therapy for HIV in Vietnam.
  
  
  METHODS
  Blood was collected during November 2009 to October 2010 from people consecutively initiating ART in four purposively selected public outpatient clinics in three Vietnamese cities. At each study site, recruitment lasted for 6-10 months until the target sample size (range 120-130 individuals) had been reached. The viral load was measured in 501 samples; 490 samples (viral load ≥1000 copies/mL) were genotyped using a nucleotide population-based sequencing assay. Self-reported demographic and clinical data were elicited through interviews. We classified drug-resistance-associated mutations (DRMs) according to the 2009 WHO surveillance list.
  
  
  RESULTS
  DRMs were identified in 17/490 participants (3.5%; 95% CI 2.2%-5.5%). The prevalence of DRMs was 1.6% (8/490) against NRTIs, 1.6% (8/490) against NNRTIs and 0.8% (4/490) against PIs; three (0.6%) participants were resistant to both NRTIs and NNRTIs. The overall prevalence of PDR to first-line drugs was low [2.7% (13/490); 95% CI 1.6%-4.4%]. The prevalence of PDR to first-line drugs was greater among 198 HIV-infected participants who injected drugs than among 286 participants who reported risks for sexually acquired HIV (4.0% versus 1.4%, P = 0.079). Multivariable logistic regression analysis suggested that PDR to first-line drugs was significantly higher among people who injected drugs (OR = 3.94; 95% CI 1.13-13.68).
  
  
  CONCLUSIONS
  With low PDR, first-line ART may be effective in Vietnam and pretreatment genotyping may be unnecessary. Continuing strategies for the prevention and surveillance of antiretroviral resistance are important for maintaining a low prevalence of antiretroviral resistance in Vietnam. The association between resistance and injection drug use warrants further research.
authors.affiliation: Department for Disease Control and Prevention, Pasteur Institute, Ho Chi Minh City, Vietnam Surveillannce and Evaluation Program for Public Health, Kirby Institute, UNSW Australia, Sydney, NSW, Australia.
authors.forename: Quang Duy
authors.initials: QD
authors.lastname: Pham
authors.affiliation: Department of HIV Care and Treatment, Vietnam Authority of HIV/AIDS Control, Hanoi, Vietnam.
authors.forename: Nhan Thi
authors.initials: NT
authors.lastname: Do
authors.affiliation: U.S. Centers for Disease Control and Prevention, Hanoi, Vietnam.
authors.forename: Yen Ngoc
authors.initials: YN
authors.lastname: Le
authors.affiliation: Department for Disease Control and Prevention, Pasteur Institute, Ho Chi Minh City, Vietnam.
authors.forename: Thuong Vu
authors.initials: TV
authors.lastname: Nguyen
authors.affiliation: U.S. Centers for Disease Control and Prevention, Hanoi, Vietnam.
authors.forename: Duc Bui
authors.initials: DB
authors.lastname: Nguyen
authors.affiliation: Department of Laboratory Analysis, Pasteur Institute, Ho Chi Minh City, Vietnam.
authors.forename: Thu Khanh Hoang
authors.initials: TK
authors.lastname: Huynh
authors.affiliation: Department of HIV Care and Treatment, Vietnam Authority of HIV/AIDS Control, Hanoi, Vietnam.
authors.forename: Duong Duc
authors.initials: DD
authors.lastname: Bui
authors.affiliation: Department for Disease Control and Prevention, Pasteur Institute, Ho Chi Minh City, Vietnam.
authors.forename: Nghia
authors.initials: N
authors.lastname: Van Khuu
authors.affiliation: Department for Disease Control and Prevention, Pasteur Institute, Ho Chi Minh City, Vietnam.
authors.forename: Phuc Duy
authors.initials: PD
authors.lastname: Nguyen
authors.affiliation: Department of Laboratory Analysis, Pasteur Institute, Ho Chi Minh City, Vietnam.
authors.forename: Anh Que
authors.initials: AQ
authors.lastname: Luong
authors.affiliation: U.S. Centers for Disease Control and Prevention, Hanoi, Vietnam.
authors.forename: Hien Thu
authors.initials: HT
authors.lastname: Bui
authors.affiliation: Department of HIV Care and Treatment, Vietnam Authority of HIV/AIDS Control, Hanoi, Vietnam.
authors.forename: Hai Huu
authors.initials: HH
authors.lastname: Nguyen
authors.affiliation: U.S. Centers for Disease Control and Prevention, Hanoi, Vietnam.
authors.forename: Michelle
authors.initials: M
authors.lastname: McConnell
authors.affiliation: Ministry of Health, Hanoi, Vietnam.
authors.forename: Long Thanh
authors.initials: LT
authors.lastname: Nguyen
authors.affiliation: Surveillannce and Evaluation Program for Public Health, Kirby Institute, UNSW Australia, Sydney, NSW, Australia.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Laboratory Analysis, Pasteur Institute, Ho Chi Minh City, Vietnam truongxuanlien@gmail.com.
authors.forename: Lien Xuan
authors.initials: LX
authors.lastname: Truong
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000494:pharmacology*; D015331:Cohort Studies; D024882:Drug Resistance, Viral; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000453:epidemiology / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D008297:Male; D015995:Prevalence; D017422:Sequence Analysis, DNA; D014744:Vietnam / Q000453:epidemiology
chemical_list: D044966:Anti-Retroviral Agents
keywords: HIV/AIDS; genotyping; resistance epidemiology; viral load