title: Inter- and intraobserver agreement in 24-hour combined multiple intraluminal impedance and pH measurement in children.
abstract: OBJECTIVE
  Assessment of intra- and interobserver agreement in multiple intraluminal impedance (MII) measurement between investigators from different institutions.
  
  
  METHODS
  Twenty-four 18- to 24-hour MII tracings were randomly chosen from 4 different institutions (6 per center). Software-aided automatic analysis was performed. Each result was validated by 2 independent investigators from the 4 different centers (4 investigator combinations). For intraobserver agreement, 6 measurements were analyzed twice by the same investigator. Agreement between investigators was calculated using the Cohen kappa coefficient.
  
  
  RESULTS
  Interobserver agreement: 13 measurements showed a perfect agreement (kappa > 0.8); 9 had a substantial (kappa 0.61-0.8), 1 a moderate (kappa coefficient 0.41 to 0.6), and 1 a fair agreement (kappa coefficient 0.11-0.4). Median kappa value was 0.83. Intraobserver agreement: 5 tracings showed perfect and 1 showed a substantial agreement. The median kappa value was 0.88.
  
  
  CONCLUSIONS
  Most measurements showed substantial to perfect intra- and interobserver agreement. Still, we found a few outliers presumably caused by poorer signal quality in some tracings rather than being observer dependent. An improvement of analysis results may be achieved by using a standard analysis protocol, a standardized method for judging tracing quality, better training options for method users, and more interaction between investigators from different institutions.
authors.affiliation: Klinik für Kinder- und Jugendmedizin, St Josef-Hospital, Universitätsklinik der Ruhr-Universität Bochum, Germany. Denisa.Pilic@gmx.de
authors.forename: Denisa
authors.initials: D
authors.lastname: Pilic
authors.forename: Carolin
authors.initials: C
authors.lastname: Höfs
authors.forename: Sandra
authors.initials: S
authors.lastname: Weitmann
authors.forename: Frank
authors.initials: F
authors.lastname: Nöh
authors.forename: Thorsten
authors.initials: T
authors.lastname: Fröhlich
authors.forename: Heino
authors.initials: H
authors.lastname: Skopnik
authors.forename: Henrik
authors.initials: H
authors.lastname: Köhler
authors.forename: Tobias G
authors.initials: TG
authors.lastname: Wenzl
authors.forename: Anjona
authors.initials: A
authors.lastname: Schmidt-Choudhury
mesh_terms: D002648:Child; D017097:Electric Impedance; D050782:Esophageal pH Monitoring / Q000592:standards*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015588:Observer Variation; D015203:Reproducibility of Results; D012984:Software