title: Assessing the impact of the requirement for explicit consent in a hospital-based stroke study.
abstract: BACKGROUND
  Increasing regulation of medical research, in particular the requirement for explicit consent, may reduce the quantity and quality of clinical epidemiological research.
  
  
  OBJECTIVE
  To assess the potential biases arising from the need for explicit consent in our hospital-based stroke research register.
  
  
  METHODS
  Comparison of patients enrolled into our stroke research register with those included in a concurrent clinical stroke audit that targeted the same population but did not require explicit consent.
  
  
  METHODS
  We obtained the numbers of consenters, refusers and those from whom consent was not sought for various logistical reasons. We compared characteristics of participants (those eventually included in the research register) vs. non-participants.
  
  
  RESULTS
  Of 1228 patients included in the stroke audit during an 18-month period, 1075 (88%) were also included in the research register, with higher participation among outpatients than inpatients. Only 1% of eligible patients refused involvement in any aspect of the research register. By far the largest number of non-participants was those from whom we could not seek consent for practical reasons. Comparison of baseline characteristics showed important differences between participants and non-participants that could affect outcome.
  
  
  CONCLUSIONS
  Very few patients refused inclusion in our research register, but the need for explicit consent reduced participation and introduced bias. An opt-out system avoiding the need for explicit patient consent for minimally intrusive clinical epidemiological studies would minimize bias and reduce the considerable time and costs associated with the consent process.
authors.affiliation: Division of Clinical Neurosciences, University of Edinburgh, Bramwell Dott Building, Western General Hospital, Edinburgh, EH4 2XU, UK.
authors.forename: C
authors.initials: C
authors.lastname: Jackson
authors.forename: L
authors.initials: L
authors.lastname: Crossland
authors.forename: M
authors.initials: M
authors.lastname: Dennis
authors.forename: J
authors.initials: J
authors.lastname: Wardlaw
authors.forename: C
authors.initials: C
authors.lastname: Sudlow
mesh_terms: D000368:Aged; D016021:Epidemiologic Studies; D005260:Female; D006302:Health Services Research / Q000941:ethics* / Q000706:statistics & numerical data; D006760:Hospitalization; D006801:Humans; D007258:Informed Consent / Q000941:ethics* / Q000706:statistics & numerical data; D008297:Male; D017063:Outcome Assessment, Health Care / Q000941:ethics / Q000706:statistics & numerical data; D018579:Patient Selection / Q000941:ethics; D045808:Refusal to Participate / Q000706:statistics & numerical data; D012606:Scotland / Q000453:epidemiology; D015983:Selection Bias; D020521:Stroke / Q000628:therapy*