title: Antiretroviral (ARV) drug resistance in the developing world.
abstract: OBJECTIVE
  To describe the overall prevalence of ARV resistance in the developing world, focusing on: (1) treatment naïve populations, (2) the resistance consequences of prevention of mother to child transmission (pMTCT) drug regimens, and (3) the relationship of medication adherence to resistance.
  
  
  METHODS
  We searched PubMed(R), EMBASE, the Cochrane Controlled Clinical Trials Register Database, and the Cochrane Database of Reviews of Effectiveness (DARE). Additional sources of evidence included the Stanford University HIV Drug Resistance Database; reports of WATCH: Worldwide Analysis of Resistance Transmission over Time of Chronically and Acute Infected HIV-1 infected persons; a recent unpublished pMTCT overview; and various conference proceedings. Studies that did not report original research, that reported data already reported in another article, and case studies of fewer than 20 individuals were excluded. Of 1,122 titles identified, 117 journal articles and presentations were included.
  
  
  METHODS
  We abstracted data on geographic region, number of participants, subject demographics, HIV viral clade, medications taken (if any), years of data collection, how people were selected for resistance testing, and how and when resistance was assessed. Because of study heterogeneity, pooling was not possible; thus, the data are summarized qualitatively. Differences by region, population group, and HIV viral clade are described.
  
  
  RESULTS
  The patterns of ARV resistance among treatment naïve populations worldwide appear to reflect geographic trends in use of ARV medications. A worldwide surveillance program (WATCH) found the rate of resistance (to any drug) among treatment naïve individuals was 5.5 percent in Africa, 7.4 percent in East Asia, 5.7 percent in Southeast Asia, and 6.4 percent in Latin America, lower than in North America (11.4 percent) and Europe (10.6 percent). Resistance data on HIV clades other than A, B, C, and D were too scarce to permit reliable conclusions. We also identified very few studies designed to assess the effect of health services delivery factors or medication adherence on the development of resistance in patients in developing countries. Evidence provided by longitudinal analyses suggests that, among women taking intrapartum single dose nevirapine (SD-NVP) to prevent mother-to-child transmission of HIV, both the overall prevalence of NNRTI resistance as well as the frequency of mutant virus in the overall viral population decreases with time since SD-NVP prophylaxis was received.
  
  
  CONCLUSIONS
  In future resistance studies, rare HIV clades should be over-sampled in order to provide statistically meaningful data. Resistance surveillance programs should be maintained throughout the developing world, and data should be reported and analyzed in a consistent and timely manner. Where resources permit, studies of adherence in developing regions should conduct resistance testing.
authors: Paul
authors: P
authors: Shekelle
authors: Margaret
authors: M
authors: Maglione
authors: Matthew Bidwell
authors: MB
authors: Geotz
authors: Glenn
authors: G
authors: Wagner
authors: Zhen
authors: Z
authors: Wang
authors: Lara
authors: L
authors: Hilton
authors: Jason
authors: J
authors: Carter
authors: Susan
authors: S
authors: Chen
authors: Carlo
authors: C
authors: Tringle
authors: Walter
authors: W
authors: Mojica
authors: Synde
authors: S
authors: Newberry
mesh_terms: D000349:Africa / Q000453:epidemiology; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D001208:Asia / Q000453:epidemiology; D002648:Child; D003906:Developing Countries; D024882:Drug Resistance, Viral; D005260:Female; D006678:HIV / Q000187:drug effects; D015658:HIV Infections / Q000188:drug therapy / Q000517:prevention & control / Q000635:transmission; D006801:Humans; D007194:India / Q000453:epidemiology; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control; D007843:Latin America / Q000453:epidemiology; D008297:Male; D019829:Nevirapine / Q000627:therapeutic use; D010349:Patient Compliance; D011247:Pregnancy; D015995:Prevalence
chemical_list: D019380:Anti-HIV Agents; D019829:Nevirapine