title: Accuracy of physician reporting in routine public health surveillance for hepatitis C virus infection.
abstract: OBJECTIVE
  From January 2007 to December 2008, the Montréal Public Health Department sent postal questionnaires to physicians and conducted patient interviews for all those newly diagnosed with hepatitis C virus (HCV) infection. We evaluated physician responses to risk factor questions for non-acute HCV cases.
  
  
  METHODS
  We compared physician and patient responses with each of nine risk factor questions, determined the sensitivity and specificity of physician responses compared with patient responses, and evaluated agreement using Gwet's agreement coefficient (AC1). We ranked risk factors and compared the distributions by principal exposure category according to physician reporting vs. patient interview using the Chi-square test.
  
  
  RESULTS
  The completeness of physicians' responses (yes, no, or unknown) varied by risk factor question from 90.8% to 96.7%. For risk factors present among more than 5% of cases, sensitivity of physician responses ranged from 26.9% to 87.7% and specificity ranged from 93.0% to 98.6%. The AC1 coefficients for agreement between physician and patient responses to lifetime risk factors considered most important in HCV acquisition were 0.80 for injection drug use, 0.95 for blood transfusion before 1990, and 0.86 for birth in a country with high HCV prevalence. Risk distributions by principal exposure category according to physician reporting vs. patient interview were not statistically different (χ(2)[4] = 2.17, p=0.704).
  
  
  CONCLUSIONS
  Postal questionnaires completed by physicians appear valid for determining the principal exposure category among non-acute HCV cases. Physician reporting can be a useful and low-cost component of routine HCV surveillance.
authors.affiliation: Public Health Department, Montréal Health and Social Services Agency, Montréal, Québec, Canada.
authors.forename: Klaus
authors.initials: K
authors.lastname: Jochem
authors.affiliation: Public Health Department, Montréal Health and Social Services Agency, Montréal, Québec, Canada ; University of Montréal, Department of Social and Preventive Medicine, Montréal, Québec, Canada.
authors.forename: Pascale
authors.initials: P
authors.lastname: Leclerc
authors.affiliation: Public Health Department, Montréal Health and Social Services Agency, Montréal, Québec, Canada.
authors.forename: Emilie
authors.initials: E
authors.lastname: Maurais
authors.affiliation: Public Health Department, Montréal Health and Social Services Agency, Montréal, Québec, Canada.
authors.forename: Claude
authors.initials: C
authors.lastname: Tremblay
authors.affiliation: Public Health Department, Montréal Health and Social Services Agency, Montréal, Québec, Canada ; McGill University, Department of Epidemiology, Biostatistics and Occupational Health, Montréal, Québec, Canada.
authors.forename: Joseph
authors.initials: J
authors.lastname: Cox
mesh_terms: D016009:Chi-Square Distribution; D006526:Hepatitis C / Q000453:epidemiology*; D006801:Humans; D010361:Patients; D010820:Physicians; D015995:Prevalence; D062486:Public Health Surveillance; D012307:Risk Factors; D011795:Surveys and Questionnaires