title: Viremia and drug resistance among HIV-1 patients on antiretroviral treatment: a cross-sectional study in Soweto, South Africa.
abstract: BACKGROUND
  We assessed risk factors for viremia and drug resistance among long-term recipients of antiretroviral therapy (ART) in South Africa.
  
  
  METHODS
  In 2008, we conducted a cross-sectional study among patients receiving ART for 12 months or more. Genotypic resistance testing was performed on individuals with a viral load higher than 400 RNA copies/ml. Multiple logistic regression analysis was used to assess associations.
  
  
  RESULTS
  Of 998 participants, 75% were women with a median age of 41 years. Most (64%) had been on treatment for more than 3 years. The prevalence of viremia was 14% (n = 139): 12% (102/883) on first-line [i.e. nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based regimen] and 33% (37/115) on second-line (i.e. protease inhibitor (PI)-based regimen) ART. Of viremic patients, 78% had drug resistance mutations. For NRTIs, NNRTIs and PIs, the prevalence of mutations was 64, 81 and 2%, respectively, among first-line failures and 29, 54 and 6%, respectively, among second-line failures. M184V/I, K103N and V106A/M were the most common mutations. Significant risk factors associated with viremia on first-line regimen included concurrent tuberculosis treatment [odds ratio (OR) 6.4, 95% confidence interval (CI) 2.2-18.8, P < 0.01] and a recent history of poor adherence (OR 2.7, 1.3-5.6, P = 0.01). Among second-line failures, attending a public clinic (OR 4.6, 95% CI 1.8-11.3, P < 0.01) and not having a refrigerator at home (OR 6.7, 95% CI 1.2-37.5, P = 0.03) were risk factors for virological failure.
  
  
  CONCLUSIONS
  Risk factors for viral failure were line regimen dependent. Second-line ART recipients had a higher rate of viremia, albeit with infrequent PI drug resistance mutations. Measures to maintain effective virologic suppression should include increased adherence counseling, attention to concomitant tuberculosis treatment and heat-stable formulations of second-line ART regimens.
authors.affiliation: Division of Global Health (IHCAR), Karolinska Institutet, Stockholm, Sweden. ziad.el-khatib@ki.se
authors.forename: Ziad
authors.initials: Z
authors.lastname: El-Khatib
authors.forename: Anna Mia
authors.initials: AM
authors.lastname: Ekstrom
authors.forename: Johanna
authors.initials: J
authors.lastname: Ledwaba
authors.forename: Lerato
authors.initials: L
authors.lastname: Mohapi
authors.forename: Fatima
authors.initials: F
authors.lastname: Laher
authors.forename: Alan
authors.initials: A
authors.lastname: Karstaedt
authors.forename: Salome
authors.initials: S
authors.lastname: Charalambous
authors.forename: Max
authors.initials: M
authors.lastname: Petzold
authors.forename: David
authors.initials: D
authors.lastname: Katzenstein
authors.forename: Lynn
authors.initials: L
authors.lastname: Morris
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods; D024882:Drug Resistance, Viral; D004812:Epidemiologic Methods; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology; D015497:HIV-1 / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D012959:Socioeconomic Factors; D013019:South Africa / Q000453:epidemiology; D017211:Treatment Failure; D019562:Viral Load; D014766:Viremia / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology
chemical_list: D019380:Anti-HIV Agents
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