title: Impact of previous virological treatment failures and adherence on the outcome of antiretroviral therapy in 2007.
abstract: BACKGROUND
  Combination antiretroviral treatment (cART) has been very successful, especially among selected patients in clinical trials. The aim of this study was to describe outcomes of cART on the population level in a large national cohort.
  
  
  METHODS
  Characteristics of participants of the Swiss HIV Cohort Study on stable cART at two semiannual visits in 2007 were analyzed with respect to era of treatment initiation, number of previous virologically failed regimens and self reported adherence. Starting ART in the mono/dual era before HIV-1 RNA assays became available was counted as one failed regimen. Logistic regression was used to identify risk factors for virological failure between the two consecutive visits.
  
  
  RESULTS
  Of 4541 patients 31.2% and 68.8% had initiated therapy in the mono/dual and cART era, respectively, and been on treatment for a median of 11.7 vs. 5.7 years. At visit 1 in 2007, the mean number of previous failed regimens was 3.2 vs. 0.5 and the viral load was undetectable (<50 copies/ml) in 84.6% vs. 89.1% of the participants, respectively. Adjusted odds ratios of a detectable viral load at visit 2 for participants from the mono/dual era with a history of 2 and 3, 4, >4 previous failures compared to 1 were 0.9 (95% CI 0.4-1.7), 0.8 (0.4-1.6), 1.6 (0.8-3.2), 3.3 (1.7-6.6) respectively, and 2.3 (1.1-4.8) for >2 missed cART doses during the last month, compared to perfect adherence. From the cART era, odds ratios with a history of 1, 2 and >2 previous failures compared to none were 1.8 (95% CI 1.3-2.5), 2.8 (1.7-4.5) and 7.8 (4.5-13.5), respectively, and 2.8 (1.6-4.8) for >2 missed cART doses during the last month, compared to perfect adherence.
  
  
  CONCLUSIONS
  A higher number of previous virologically failed regimens, and imperfect adherence to therapy were independent predictors of imminent virological failure.
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Marie
authors.initials: M
authors.lastname: Ballif
authors.forename: Bruno
authors.initials: B
authors.lastname: Ledergerber
authors.forename: Manuel
authors.initials: M
authors.lastname: Battegay
authors.forename: Matthias
authors.initials: M
authors.lastname: Cavassini
authors.forename: Enos
authors.initials: E
authors.lastname: Bernasconi
authors.forename: Patrick
authors.initials: P
authors.lastname: Schmid
authors.forename: Bernard
authors.initials: B
authors.lastname: Hirschel
authors.forename: Hansjakob
authors.initials: H
authors.lastname: Furrer
authors.forename: Martin
authors.initials: M
authors.lastname: Rickenbach
authors.forename: Milos
authors.initials: M
authors.lastname: Opravil
authors.forename: Rainer
authors.initials: R
authors.lastname: Weber
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000494:pharmacology / Q000627:therapeutic use*; D015331:Cohort Studies; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000188:drug therapy*; D015497:HIV-1 / Q000187:drug effects; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D018579:Patient Selection; D012367:RNA, Viral / Q000235:genetics; D013557:Switzerland; D017211:Treatment Failure; D019562:Viral Load / Q000187:drug effects
chemical_list: D044966:Anti-Retroviral Agents; D012367:RNA, Viral