title: Major influence of interobserver reliability on polytrauma identification with the Injury Severity Score (ISS): Time for a centralised coding in trauma registries?
abstract: OBJECTIVE
  The Abbreviated Injury Scale (AIS) and the Injury Severity Score (ISS) find increasingly widespread use to assess trauma burden and to perform interhospital benchmarking through trauma registries. Since 2015, public resource allocation in Switzerland shall even be derived from such data. As every trauma centre is responsible for its own coding and data input, this study aims at evaluating interobserver reliability of AIS and ISS coding.
  
  
  METHODS
  Interobserver reliability of the AIS and ISS is analysed from a cohort of 50 consecutive severely injured patients treated in 2012 at our institution, coded retrospectively by 3 independent and specifically trained observers.
  
  
  RESULTS
  Considering a cutoff ISS≥16, only 38/50 patients (76%) were uniformly identified as polytraumatised or not. Increasing the cut off to ≥20, this increased to 41/50 patients (82%). A difference in the AIS of ≥ 1 was present in 261 (16%) of possible codes. Excluding the vast majority of uninjured body regions, uniformly identical AIS severity values were attributed in 67/193 (35%) body regions, or 318/579 (55%) possible observer pairings.
  
  
  CONCLUSIONS
  Injury severity all too often is neither identified correctly nor consistently when using the AIS. This leads to wrong identification of severely injured patients using the ISS. Improving consistency of coding through centralisation is recommended before scores based on the AIS are to be used for interhospital benchmarking and resource allocation in the treatment of severely injured patients.
authors.affiliation: Division for Orthopaedic and Trauma Surgery, Cantonal Hospital, Winterthur, Switzerland.
authors.forename: Roman
authors.initials: R
authors.lastname: Maduz
authors.affiliation: Division for Orthopaedic and Trauma Surgery, Cantonal Hospital, Winterthur, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Kugelmeier
authors.affiliation: Division for Orthopaedic and Trauma Surgery, Cantonal Hospital, Winterthur, Switzerland.
authors.forename: Severin
authors.initials: S
authors.lastname: Meili
authors.affiliation: Division for Orthopaedic and Trauma Surgery, Cantonal Hospital, Winterthur, Switzerland.
authors.forename: Robert
authors.initials: R
authors.lastname: Döring
authors.affiliation: Division for Orthopaedic and Trauma Surgery, Cantonal Hospital, Winterthur, Switzerland. Electronic address: christoph.meier@ksw.ch.
authors.forename: Christoph
authors.initials: C
authors.lastname: Meier
authors.affiliation: Division for Orthopaedic and Trauma Surgery, Cantonal Hospital, Winterthur, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Wahl
mesh_terms: D015998:Abbreviated Injury Scale; D019985:Benchmarking; D002648:Child; D059019:Clinical Coding; D002983:Clinical Competence / Q000592:standards*; D006801:Humans; D015601:Injury Severity Score; D009104:Multiple Trauma / Q000175:diagnosis* / Q000628:therapy; D011446:Prospective Studies; D012042:Registries; D015203:Reproducibility of Results; D013557:Switzerland / Q000453:epidemiology; D014193:Trauma Centers
keywords: AIS; Abbreviated injury scale; ISS; Injury severity score; Interobserver reliability; Polytrauma