title: [Analysis of variables associated to undetectable viral load and therapeutic failure in HIV-infected individuals].
abstract: BACKGROUND
  To date, antiretroviral therapies have not led to total HIV eradication in infected individuals. The achievement of undetectable viremia levels has been regarded as essential when monitorizing the efficacy of these therapies. The objectives of our study were to assess the time needed to achieve viral load (VL) undetectable levels and subsequent VL risings, as well as to determine the clinical variables associated with both events.
  
  
  METHODS
  Owing to a follow-up period greater than 1,000 days, 314 patients were retrospectively selected. We determined the percentages of patients with undetectable VL levels and of those with subsequent VL rising. Times needed to reach both events were calculated by Kaplan-Meier analysis.
  
  
  RESULTS
  182 individuals (58%; 95% CI, 52.3-63.5) reached undetectable VL levels with a median follow-up time of 862 days. A more regular VL quantitation was associated with such event. The VL level of 38 out of these individuals (20.9%; 95% CI, 15.2-27.5) increased subsequently (> 30,000 RNA copies/ml) with a mean time of 328 days (after the first undetectable VL determination); this event was associated with changes in the clinical centre where the patient was being cared for.
  
  
  CONCLUSIONS
  In our series, the proportion of individuals with undetectable VL levels and therapeutic failure was low. The frequency of VL determination was a determining factor in the evolution of these patients.
authors.affiliation: Servicio y Area de Microbiología, Hospital Clínico Universitario y Facultad de Medicina, Valladolid, Spain. eiros@med.uva.es
authors.forename: José María
authors.initials: JM
authors.lastname: Eiros
authors.forename: Agustín
authors.initials: A
authors.lastname: Mayo
authors.forename: María del Pilar
authors.initials: Mdel P
authors.lastname: Ortega Md
authors.forename: Beatriz
authors.initials: B
authors.lastname: Hernández
authors.forename: Cristina
authors.initials: C
authors.lastname: Labayru
authors.forename: Raúl
authors.initials: R
authors.lastname: Ortiz De Lejarazu
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D016009:Chi-Square Distribution; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000188:drug therapy* / Q000635:transmission / Q000821:virology*; D015497:HIV-1 / Q000235:genetics; D006801:Humans; D008297:Male; D012367:RNA, Viral / Q000032:analysis; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000150:complications; D016019:Survival Analysis; D013997:Time Factors; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral