title: Risk communication in clinical trials: a cognitive experiment and a survey.
abstract: BACKGROUND
  A Royal Statistical Society Working Party recently recommended that "Greater use should be made of numerical, as opposed to verbal, descriptions of risk" in first-in-man clinical trials. This echoed the view of many clinicians and psychologists about risk communication. As the clinical trial industry expands rapidly across the globe, it is important to understand risk communication in Asian countries.
  
  
  METHODS
  We conducted a cognitive experiment about participation in a hypothetical clinical trial of a pain relief medication and a survey in cancer and arthritis patients in Singapore. In part 1 of the experiment, the patients received information about the risk of side effects in one of three formats (frequency, percentage and verbal descriptor) and in one of two sequences (from least to most severe and from most to least severe), and were asked about their willingness to participate. In part 2, the patients received information about the risk in all three formats, in the same sequence, and were again asked about their willingness to participate. A survey of preference for risk presentation methods and usage of verbal descriptors immediately followed.
  
  
  RESULTS
  Willingness to participate and the likelihood of changing one's decision were not affected by the risk presentation methods. Most patients indicated a preference for the frequency format, but patients with primary school or no formal education were indifferent. While the patients used the verbal descriptors "very common", "common" and "very rare" in ways similar to the European Commission's Guidelines, their usage of the descriptors "uncommon" and "rare" was substantially different from the EU's.
  
  
  CONCLUSIONS
  In this sample of Asian cancer and arthritis patients, risk presentation format had no impact on willingness to participate in a clinical trial. However, there is a clear preference for the frequency format. The lay use of verbal descriptors was substantially different from the EU's.
authors.affiliation: Center for Quantitative Medicine, Duke-NUS Graduate Medical School, College Road 169857, Singapore. yinbun.cheung@scri.edu.sg
authors.forename: Yin Bun
authors.initials: YB
authors.lastname: Cheung
authors.forename: Hwee Lin
authors.initials: HL
authors.lastname: Wee
authors.forename: Julian
authors.initials: J
authors.lastname: Thumboo
authors.forename: Cynthia
authors.initials: C
authors.lastname: Goh
authors.forename: Ricardo
authors.initials: R
authors.lastname: Pietrobon
authors.forename: Han Chong
authors.initials: HC
authors.lastname: Toh
authors.forename: Yu Fen
authors.initials: YF
authors.lastname: Yong
authors.forename: Say Beng
authors.initials: SB
authors.lastname: Tan
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001168:Arthritis / Q000175:diagnosis / Q000523:psychology*; D002986:Clinical Trials as Topic; D003657:Decision Making; D004522:Educational Status; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D017533:Marital Status; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis / Q000523:psychology*; D010342:Patient Acceptance of Health Care / Q000523:psychology* / Q000706:statistics & numerical data; D010353:Patient Education as Topic / Q000379:methods; D010358:Patient Participation / Q000523:psychology; D057240:Patient Preference; D012306:Risk; D040242:Risk Reduction Behavior; D012846:Singapore; D014705:Verbal Behavior