title: [Comparison of two methods to assess causality of adverse drug reactions].
abstract: BACKGROUND
  Assessment of causality is an essential part of pharmacological surveillance.
  
  
  OBJECTIVE
  To compare the causality assessment of suspected adverse drug reactions (ADRs) using algorithms proposed by Karch-Lasagna (K & L) and the World Health Organization (WHO).
  
  
  METHODS
  All spontaneous reports of suspected ADRs in a pediatric ward of a regional hospital were included. Causality was categorized as definitive, probable, possible, conditional or unlikely. The agreement between K & L and WHO algorithms was assessed using binomial test proportions and kappa coefficients.
  
  
  RESULTS
  One hundred thirty reports of ADRs in 126 patients aged 2 to 11 years were analyzed. The suspected medications were antineoplastic drugs in 59% of cases and antimicrobials in 23%. The most common affected system was the skin and appendages in 35%. Using K & L algorithm, causality was categorized as definitive in 10% of cases, probable in 28.5%, possible in 35.4%, conditional in 23.1% and unlikely in 3.0%. Using WHO algorithm, the figures were 2.3, 34.6, 59.2, 2.3 and 1.5%, respectively. The degree of agreement between K & L and WHO algorithms was 32.3% (kappa = 0.004).
  
  
  CONCLUSIONS
  K & L attributed a higher level of ADR causality than WHO algorithm.
authors.forename: Mónica
authors.initials: M
authors.lastname: Kyonen
authors.forename: Isabel
authors.initials: I
authors.lastname: Folatre
authors.forename: Ximena
authors.initials: X
authors.lastname: Lagos
authors.forename: Silvia
authors.initials: S
authors.lastname: Vargas
mesh_terms: D000293:Adolescent; D016907:Adverse Drug Reaction Reporting Systems; D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D064420:Drug-Related Side Effects and Adverse Reactions / Q000145:classification; D006801:Humans; D007223:Infant; D014944:World Health Organization