title: Reliability of quantification measures of actinic keratosis.
abstract: BACKGROUND
  Enumerating actinic keratoses (AKs) is highly variable but important to standardize as new therapies are emerging.
  
  
  OBJECTIVE
  To assess the reliability of four different methods used to quantify AKs and to investigate whether a consensus meeting affects the reliability.
  
  
  METHODS
  This was a single-blinded study of 12 experienced dermatologist raters counting AKs on the face and ears of nine subjects before and after a consensus meeting. Raters were recruited from investigators of a multicentre Veterans Affairs cooperative study. The intraclass correlation coefficient (ICC) among raters for pre- and post-consensus evaluations was the primary outcome measure.
  
  
  RESULTS
  Of the four assessment methods, the 'total count' method had the greatest ICC for both pre- (0·18, P = 0·04) and post-consensus (0·66, P = < 0·0001) assessments. Total count was also the only pre-consensus ICC for which the null hypothesis of no association among assessments was rejected.
  
  
  CONCLUSIONS
  Total AK count appears to be the most reliable measure of quantifying AKs on the face and ears. Educational consensus discussion prior to assessment improves reliability of this measure.
authors.affiliation: Division of Dermatology, Department of Veterans Affairs Medical Center, Decatur, GA, U.S.A; Department of Dermatology, Emory University, Atlanta, GA, U.S.A.
authors.forename: S C
authors.initials: SC
authors.lastname: Chen
authors.forename: N D
authors.initials: ND
authors.lastname: Hill
authors.forename: E
authors.initials: E
authors.lastname: Veledar
authors.forename: S M
authors.initials: SM
authors.lastname: Swetter
authors.forename: M A
authors.initials: MA
authors.lastname: Weinstock
mesh_terms: D002983:Clinical Competence / Q000592:standards*; D032921:Consensus; D003880:Dermatology / Q000592:standards*; D005260:Female; D006801:Humans; D055623:Keratosis, Actinic / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D016037:Single-Blind Method