title: Population-based surveillance of HIV drug resistance emerging on treatment and associated factors at sentinel antiretroviral therapy sites in Namibia.
abstract: OBJECTIVE
  The World Health Organization (WHO) prospective surveys of acquired HIV drug resistance (HIVDR) evaluate HIVDR emerging after the first year of antiretroviral therapy (ART) and associated factors.
  
  
  METHODS
  Consecutive ART starters in 2009 were enrolled at 3 sentinel sites in Namibia. Genotyping was performed at start and after 12 months in patients with HIV viral load (VL) >1000 copies per mL. HIVDR outcomes were: HIVDR prevention (VL ≤1000 copies/mL), possible HIVDR (VL >1000 copies/mL without detectable HIVDR or loss to follow-up or ART stop), and HIVDR (VL >1000 copies/mL with detectable HIVDR). Adherence was assessed using medication possession ratio (MPR).
  
  
  RESULTS
  Of 394 starters, at 12 months, 80% were on first-line ART, 1% died, 4% transferred out, 1% stopped ART, <1% switched to second-line, and 15% were lost to follow-up. Among patients on first-line, 77% had VL testing, and 94% achieved VL ≤1000 copies per mL. At baseline, 7% had HIVDR. After 12 months, among patients with VL testing, 5% had HIVDR. A majority of patients failing therapy had high-level resistance to nonnucleoside reverse transcriptase inhibitors but none to protease inhibitors. All sites achieved the WHO target of ≥70% HIVDR prevention. Factors associated with not achieving HIVDR prevention were: baseline resistance to nonnucleoside reverse transcriptase inhibitors [odds ratio (OR) 3.0, P = 0.023], WHO stage 3 or 4 at baseline (OR 2.0, P = 0.012), and MPR <75% (OR 4.9, P = 0.021).
  
  
  CONCLUSIONS
  Earlier ART initiation and removal of barriers to on-time drug pickups may help to prevent HIVDR. These data inform decisions at national and global levels on the effectiveness of first- and second-line regimens.
authors.affiliation: *Department of Public Health and Community Medicine, Tufts University School of Medicine, Boston, MA; †Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, MA; ‡Republic of Namibia Ministry of Health and Social Services, Windhoek, Namibia; §Molecular Diagnosis Unit, Namibia Institute of Pathology, Windhoek, Namibia; ‖World Health Organization, Klein Windhoek, Windhoek, Namibia; and ¶Centre for HIV & STIs: HIV Virology Section, National Institute for Communicable Diseases, Johannesburg, South Africa.
authors.forename: Steven Y
authors.initials: SY
authors.lastname: Hong
authors.forename: Anna
authors.initials: A
authors.lastname: Jonas
authors.forename: Michael
authors.initials: M
authors.lastname: DeKlerk
authors.forename: Andreas
authors.initials: A
authors.lastname: Shiningavamwe
authors.forename: Tiruneh
authors.initials: T
authors.lastname: Desta
authors.forename: Alfons
authors.initials: A
authors.lastname: Badi
authors.forename: Lynn
authors.initials: L
authors.lastname: Morris
authors.forename: Gillian M
authors.initials: GM
authors.lastname: Hunt
authors.forename: Johanna
authors.initials: J
authors.lastname: Ledwaba
authors.forename: Heidi B
authors.initials: HB
authors.lastname: Sheehan
authors.forename: Kiger
authors.initials: K
authors.lastname: Lau
authors.forename: Andrew
authors.initials: A
authors.lastname: Trotter
authors.forename: Alice M
authors.initials: AM
authors.lastname: Tang
authors.forename: Christine
authors.initials: C
authors.lastname: Wanke
authors.forename: Michael R
authors.initials: MR
authors.lastname: Jordan
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000600:supply & distribution / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods; D024882:Drug Resistance, Viral; D005260:Female; D005838:Genotype; D060005:Genotyping Techniques; D006678:HIV / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology*; D006801:Humans; D008297:Male; D009276:Namibia; D011446:Prospective Studies; D018571:Sentinel Surveillance
chemical_list: D044966:Anti-Retroviral Agents