title: Risk factors of treatment-limiting anemia after substitution of zidovudine for stavudine in HIV-infected adult patients on antiretroviral treatment.
abstract: BACKGROUND
  Anemia is the main concern among patients using a zidovudine (AZT)-based antiretroviral treatment (ART). Some studies suggested weight-adjusted AZT dosing as a way to reduce toxicity. We analyzed the risk factors associated with AZT-induced anemia in a cohort using AZT as substitution for stavudine (D4T).
  
  
  METHODS
  We retrospectively studied HIV-infected patients in a referral hospital in Phnom Penh, Cambodia between 2003 and 2011. Factors associated with AZT-related anemia requiring AZT-discontinuation within the first year after AZT initiation were analyzed using Cox regression.
  
  
  RESULTS
  Overall, 1180 patients, 60.5% female, were included. At AZT initiation, the median hemoglobin was 12.7 g/dL (IQR 11.7-13.9), the median weight: 51 kg (IQR 45-58) and the median time on ART prior to AZT substitution: 1.4 years (IQR 1.0-2.0). Within one year follow-up, 139 patients (11.8%) developed anemia requiring AZT discontinuation. Overall, there was no independent association of body weight with AZT discontinuation. AZT discontinuation was associated with lower hemoglobin level when starting AZT; older age and taking D4T-based ART less than one year prior to AZT. In exploratory analysis, a linear increase in risk of grade 2-4 anemia with lower body weight was seen if starting AZT substitution within less than one year of D4T-based ART.
  
  
  CONCLUSIONS
  Our findings argue against the need of weight-based dosing of AZT to reduce anemia among patients using AZT as substitution for D4T. Whether this also applies to ART-naïve individuals remains to be assessed. Future studies with AZT dose reduction should assess efficacy and overall tolerance of AZT.
authors.affiliation: Department of Infectious Diseases, Sihanouk Hospital Center of HOPE, Phnom Penh, Cambodia. thongphe@sihosp.org
authors.forename: Thong
authors.initials: T
authors.lastname: Phe
authors.forename: Sopheak
authors.initials: S
authors.lastname: Thai
authors.forename: Chhunheng
authors.initials: C
authors.lastname: Veng
authors.forename: Sopheak
authors.initials: S
authors.lastname: Sok
authors.forename: Lutgarde
authors.initials: L
authors.lastname: Lynen
authors.forename: Johan
authors.initials: J
authors.lastname: van Griensven
mesh_terms: D000328:Adult; D000740:Anemia / Q000139:chemically induced*; D019380:Anti-HIV Agents / Q000009:adverse effects* / Q000627:therapeutic use*; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D018119:Stavudine / Q000009:adverse effects / Q000627:therapeutic use*; D015215:Zidovudine / Q000009:adverse effects* / Q000627:therapeutic use*
chemical_list: D019380:Anti-HIV Agents; D015215:Zidovudine; D018119:Stavudine
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