title: Patients' expectations about the benefit of antibiotic treatment: lessons from a randomised controlled trial.
abstract: BACKGROUND
  Patient expectations may be an important component of a placebo effect, and yet few studies assess how patients' pre-existing expectations affect subsequent health outcomes.
  
  
  OBJECTIVE
  To estimate the association between patients' expectations and time to cure in patients with clinically diagnosed acute bacterial rhinosinusitis.
  
  
  METHODS
  In a randomised controlled trial, expectations about the benefit of an antibiotic therapy were measured prior to treatment with either an antibiotic or placebo.
  
  
  RESULTS
  Of the patients asked for consent, 64% refused mostly because they either wanted or did not want to receive antibiotics. Over 25% of the patients who gave consent were ambivalent about the benefit of antibiotic therapy. Predictably there was no evidence of an association between expectations and time to cure in those that gave consent.
  
  
  CONCLUSIONS
  Selection bias occurs if patients with strong expectations refuse to participate in a trial and if the success of the intervention depends in part on a patient's expectations. Methods that adjust for selection bias are recommended for trials where placebo effects are either of interest or could be an important component of an intervention.
authors.affiliation: Institut für klinische Epidemiologie, Universitätsspital Basel, Switzerland. jyoung@uhbs.ch
authors.forename: Jim
authors.initials: J
authors.lastname: Young
authors.forename: Christa
authors.initials: C
authors.lastname: Hugenschmidt
authors.forename: Antje
authors.initials: A
authors.lastname: Welge-Lüssen
authors.forename: Heiner C
authors.initials: HC
authors.lastname: Bucher
authors.forename: Peter
authors.initials: P
authors.lastname: Tschudi
authors.forename: Pierre
authors.initials: P
authors.lastname: Périat
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D004311:Double-Blind Method; D006801:Humans; D015990:Placebo Effect; D016016:Proportional Hazards Models; D012220:Rhinitis / Q000188:drug therapy*; D015983:Selection Bias; D012720:Severity of Illness Index; D012852:Sinusitis / Q000188:drug therapy*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents