title: Is expert opinion reliable when estimating transition probabilities? The case of HCV-related cirrhosis in Egypt.
abstract: BACKGROUND
  Data on HCV-related cirrhosis progression are scarce in developing countries in general, and in Egypt in particular. The objective of this study was to estimate the probability of death and transition between different health stages of HCV (compensated cirrhosis, decompensated cirrhosis and hepatocellular carcinoma) for an Egyptian population of patients with HCV-related cirrhosis.
  
  
  METHODS
  We used the "elicitation of expert opinions" method to obtain collective knowledge from a panel of 23 Egyptian experts (among whom 17 were hepatologists or gastroenterologists and 2 were infectiologists). The questionnaire was based on virtual medical cases and asked the experts to assess probability of death or probability of various cirrhosis complications. The design was a Delphi study: we attempted to obtain a consensus between experts via a series of questionnaires interspersed with group response feedback.
  
  
  RESULTS
  We found substantial disparity between experts' answers, and no consensus was reached at the end of the process. Moreover, we obtained high death probability and high risk of hepatocellular carcinoma. The annual transition probability to death was estimated at between 10.1% and 61.5% and the annual probability of occurrence of hepatocellular carcinoma was estimated at between 16.8% and 58.9% (depending on age, gender, time spent in cirrhosis and cirrhosis severity).
  
  
  CONCLUSIONS
  Our results show that eliciting expert opinions is not suited for determining the natural history of diseases due to practitioners' difficulties in evaluating quantities. Cognitive bias occurring during this type of study might explain our results.
authors.affiliation: IAME, UMR 1137, INSERM, F-75018 Paris, France; Univ Paris Diderot, Sorbonne Paris Cité, F-75018 Paris, France. anthony.cousien@gmail.com.
authors.forename: Anthony
authors.initials: A
authors.lastname: Cousien
authors.forename: Dorothée
authors.initials: D
authors.lastname: Obach
authors.forename: Sylvie
authors.initials: S
authors.lastname: Deuffic-Burban
authors.forename: Aya
authors.initials: A
authors.lastname: Mostafa
authors.forename: Gamal
authors.initials: G
authors.lastname: Esmat
authors.forename: Valérie
authors.initials: V
authors.lastname: Canva
authors.forename: Mohamed
authors.initials: M
authors.lastname: El Kassas
authors.forename: Mohammad
authors.initials: M
authors.lastname: El-Sayed
authors.forename: Wagida A
authors.initials: WA
authors.lastname: Anwar
authors.forename: Arnaud
authors.initials: A
authors.lastname: Fontanet
authors.forename: Mostafa K
authors.initials: MK
authors.lastname: Mohamed
authors.forename: Yazdan
authors.initials: Y
authors.lastname: Yazdanpanah
mesh_terms: D000328:Adult; D006528:Carcinoma, Hepatocellular / Q000453:epidemiology / Q000401:mortality* / Q000821:virology; D032921:Consensus; D018450:Disease Progression; D004534:Egypt / Q000453:epidemiology; D005260:Female; D016174:Hepacivirus; D006526:Hepatitis C / Q000453:epidemiology / Q000401:mortality* / Q000821:virology; D006801:Humans; D008103:Liver Cirrhosis / Q000453:epidemiology / Q000401:mortality* / Q000821:virology; D008113:Liver Neoplasms / Q000453:epidemiology / Q000401:mortality* / Q000821:virology; D008297:Male; D008875:Middle Aged; D011795:Surveys and Questionnaires