title: Social and environmental predictors of plasma HIV RNA rebound among injection drug users treated with antiretroviral therapy.
abstract: BACKGROUND
  Evidence is needed to improve HIV treatment outcomes for individuals who use injection drugs (IDU). Although studies have suggested higher rates of plasma viral load (PVL) rebound among IDU on antiretroviral therapy (ART), risk factors for rebound have not been thoroughly investigated.
  
  
  METHODS
  We used data from a long-running community-recruited prospective cohort of IDU in Vancouver, Canada, linked to comprehensive ART and clinical monitoring records. Using proportional hazards methods, we modeled the time to confirmed PVL rebound above 1000 copies per milliliter among IDU on ART with sustained viral suppression, defined as 2 consecutive undetectable PVL measures.
  
  
  RESULTS
  Between 1996 and 2009, 277 individuals had sustained viral suppression. Over a median follow-up of 32 months, 125 participants (45.1%) experienced at least 1 episode of virologic failure for an incidence of 12.6 [95% confidence interval (CI): 10.5 to 15.0] per 100 person-years. In a multivariate model, PVL rebound was independently associated with sex-trade involvement [adjusted hazard ratio (AHR) = 1.40, 95% CI: 1.08 to 1.82) and recent incarceration (AHR = 1.83, 95% CI: 1.33 to 2.52). Methadone maintenance therapy (AHR = 0.79, 95% CI: 0.66 to 0.94) was protective. No measure of illicit drug use was predictive.
  
  
  CONCLUSIONS
  In this setting of free ART, several social and environmental factors predicted higher risks of viral rebound among IDU, including sex-trade involvement and incarceration. These findings should help inform efforts to identify individuals at risk of viral rebound and targeted interventions to treat and retain individuals in effective ART.
authors: British Columbia Centre for Excellence in HIV/AIDS, St Paul's Hospital, Vancouver, Canada.
authors: M-J
authors: MJ
authors: Milloy
authors: Thomas
authors: T
authors: Kerr
authors: Jane
authors: J
authors: Buxton
authors: Tim
authors: T
authors: Rhodes
authors: Andrea
authors: A
authors: Krusi
authors: Silvia
authors: S
authors: Guillemi
authors: Robert
authors: R
authors: Hogg
authors: Julio
authors: J
authors: Montaner
authors: Evan
authors: E
authors: Wood
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D001955:British Columbia; D005260:Female; D015658:HIV Infections / Q000097:blood* / Q000188:drug therapy*; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D008297:Male; D008691:Methadone / Q000627:therapeutic use; D008875:Middle Aged; D058850:Opiate Substitution Treatment; D011329:Prisoners; D011446:Prospective Studies; D012367:RNA, Viral / Q000097:blood*; D011477:Sex Work; D015819:Substance Abuse, Intravenous / Q000150:complications* / Q000821:virology; D019562:Viral Load / Q000187:drug effects
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral; D008691:Methadone