title: Opt-out as an acceptable method of obtaining consent in medical research: a short report.
abstract: BACKGROUND
  A prospective cohort study was set up to investigate a possible association between antibiotic prescribing and antibiotic resistance of E. coli urinary tract infection in the community. Participation of patients with urinary tract infection was obtained through an opt-out methodology. This short paper reports on the acceptability of the opt-out recruitment approach.
  
  
  METHODS
  Participating practices (22) were requested to send a urine sample from all patients presenting with symptoms of urinary tract infection. Upon receipt of the sample in the laboratory, a letter explaining the study, an opt-out form and a freepost envelope were sent to all adult patients. A website with additional information and including an 'opt-out' button was set up for the study.
  
  
  RESULTS
  A total of 1362 urine samples were submitted by the 22 participating practices representing 1178 adult patients of whom 193 actively responded to the letter: 142 opted out by letter, 15 through the website, 2 by phone and 12 sent the letter back without indication, making a total of 171 patients or 14.5% opt-out; the remaining 22 patients (1.9%) explicitly opted in. The total group consisted of 80% women and the mean age was 50.9 years (sd 20.8). No significant differences were found between patients who participated and those who opted out in terms of age, gender or whether the urine sample was positive or not.
  
  
  CONCLUSIONS
  Overall the opt-out method was well received and participation in the study reached 85.5%. The low number of complaints (2) indicates that this is a generally acceptable method of patient recruitment. The 14.5% opt-out shows that it effectively empowers patients to decline participation. The similarity between patients opting out and the rest of the patients is reassuring for extrapolation of the results of the study.
authors.affiliation: Discipline of General Practice, School of Medicine, NUI Galway, Ireland. akke.vellinga@nuigalway.ie
authors.forename: Akke
authors.initials: A
authors.lastname: Vellinga
authors.forename: Martin
authors.initials: M
authors.lastname: Cormican
authors.forename: Belinda
authors.initials: B
authors.lastname: Hanahoe
authors.forename: Kathleen
authors.initials: K
authors.lastname: Bennett
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Murphy
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D035843:Biomedical Research; D015331:Cohort Studies; D032962:Consent Forms; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects; D005260:Female; D006801:Humans; D007258:Informed Consent; D008297:Male; D008875:Middle Aged; D010358:Patient Participation; D018579:Patient Selection; D045808:Refusal to Participate; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000382:microbiology / Q000652:urine
chemical_list: D000900:Anti-Bacterial Agents