title: Validity and reliability of the Brazilian birth certificate for reporting birth defects.
abstract: OBJECTIVE
  We sought to assess data validity and coding reliability of birth defects among Brazilian birth certificates (BC).
  
  
  METHODS
  From a population of 27,945 live births delivered at 8 hospitals in 7 cities of Brazil during 2004, we compared 677 cases of birth defects identified through BC to 1,110 cases identified through a hospital-based birth defect registry.
  
  
  RESULTS
  Birth defects prevalence according to BC varied by hospital from 0.5% to 5.3%. Birth certificate sensitivity of birth defects reporting varied by hospital, from 11.4% to 66.5%. Specificity and positive and negative predictive values were above 80%. For reported cases, concordance of diagnosis was over 90% for all hospitals combined. Birth defects coding reliability, determined by kappa statistics, varied from 0.61 to 1.00 for 3-digit ICD-10 codes and 0.41 to 0.78 for 4-digit codes.
  
  
  CONCLUSIONS
  Birth certificate data underestimated birth defects prevalence among live births. Although concordance of diagnosis was high, the data should be used cautiously because of high underreporting and moderate coding reliability.
authors.affiliation: Post-graduation Program Environment and Public Health National School of Public Health, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil. luquetti@uw.edu
authors.forename: Daniela Varela
authors.initials: DV
authors.lastname: Luquetti
authors.forename: Rosalina Jorge
authors.initials: RJ
authors.lastname: Koifman
mesh_terms: D001719:Birth Certificates; D001938:Brazil / Q000453:epidemiology; D000013:Congenital Abnormalities / Q000453:epidemiology*; D016208:Databases, Factual; D006801:Humans; D015995:Prevalence; D012042:Registries / Q000592:standards; D015203:Reproducibility of Results