title: Persistent low-level viraemia and virological failure in HIV-1-infected patients treated with highly active antiretroviral therapy.
abstract: OBJECTIVE
  To assess the prognostic significance of persistent low-level viraemia (PLV, defined as persistent plasma viral loads of 51-1000 HIV-1 RNA copies/mL for at least 3 months) in patients who had achieved viral suppression on antiretroviral therapy (ART).
  
  
  METHODS
  A retrospective cohort of HIV-infected patients who received ART, were followed-up for > or =12 months, made regular visits to the clinic during which blood tests were performed for an ultrasensitive HIV RNA assay every 3 months, and achieved viral loads <50 copies/mL were evaluated. Virological failure was defined as two consecutive viral load measurements >1000 copies/mL.
  
  
  RESULTS
  Of 362 patients, 78 (27.5%) experienced PLV. The demographics of patients with and without PLV were similar. PLV occurred at a mean (+/-standard deviation) of 22.6+/-16.9 months after ART initiation and lasted for 6.4+/-3.4 months. During a median follow-up of 29.5 months, patients with PLV had a higher rate of virological failure (39.7% vs 9.2%; P < 0.001). The median time to failure was 68.4 months [95% confidence interval (CI) 37.0-99.7] for patients with PLV and >72 months for patients without PLV (log rank test, P < 0.001). By Cox regression, patients with PLV had a greater risk of virological failure [hazard ratio (HR) 3.8; 95% CI 2.2-6.4; P < 0.001]. Among patients with PLV, a PLV of >400 copies/mL (HR 3.3; 95% CI 1.5-7.1; P = 0.003) and a history of ART (HR 2.4; 95% CI 1.0-5.7; P = 0.042) predicted virological failure.
  
  
  CONCLUSIONS
  PLV is associated with virological failure. Patients with a PLV >400 copies/mL and a history of ART experience are more likely to experience virological failure. Patients with PLV should be considered for treatment optimization and interventional studies.
authors.affiliation: Washington University School of Medicine, St Louis, MO, USA. ssungkanuparph@yahoo.com
authors.forename: S
authors.initials: S
authors.lastname: Sungkanuparph
authors.forename: R K
authors.initials: RK
authors.lastname: Groger
authors.forename: E T
authors.initials: ET
authors.lastname: Overton
authors.forename: V J
authors.initials: VJ
authors.lastname: Fraser
authors.forename: W G
authors.initials: WG
authors.lastname: Powderly
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology; D015497:HIV-1; D006801:Humans; D008297:Male; D011379:Prognosis; D012367:RNA, Viral / Q000097:blood; D012189:Retrospective Studies; D012307:Risk Factors; D017211:Treatment Failure; D019562:Viral Load; D014766:Viremia / Q000821:virology*
chemical_list: D012367:RNA, Viral