title: Trauma and Injury Severity Score (TRISS) coefficients 2009 revision.
abstract: BACKGROUND
  Currently used Trauma and Injury Severity Score (TRISS) coefficients, which measure probability of survival (PS), were derived from the Major Trauma Outcome Study (MTOS) in 1995 and are now unlikely to be optimal. This study aims to estimate new TRISS coefficients using a contemporary database of injured patients presenting to emergency departments in the United States; and to compare these against the MTOS coefficients.
  
  
  METHODS
  Data were obtained from the National Trauma Data Bank (NTDB) and the NTDB National Sample Project (NSP). TRISS coefficients were estimated using logistic regression. Separate coefficients were derived from complete case and multistage multiple imputation analyses for each NTDB and NSP dataset. Associated PS over Injury Severity Score values were graphed and compared by age (adult >or=15 years; pediatric <15 years) and injury mechanism (blunt; penetrating) groups. Area under the Receiver Operating Characteristic curves was used to assess coefficients' predictive performance.
  
  
  RESULTS
  Overall 1,072,033 NTDB and 1,278,563 weighted NSP injury events were included, compared with 23,177 used in the original MTOS analyses. Large differences were seen between results from complete case and imputed analyses. For blunt mechanism and adult penetrating mechanism injuries, there were similarities between coefficients estimated on imputed samples, and marked divergences between associated PS estimates and those from the MTOS. However, negligible differences existed between area under the receiver operating characteristic curves estimates because the overwhelming majority of patients had minor trauma and survived. For pediatric penetrating mechanism injuries, variability in coefficients was large and PS estimates unreliable.
  
  
  CONCLUSIONS
  Imputed NTDB coefficients are recommended as the TRISS coefficients 2009 revision for blunt mechanism and adult penetrating mechanism injuries. Coefficients for pediatric penetrating mechanism injuries could not be reliably estimated.
authors.affiliation: School of Public Health and Psychosocial Studies, AUT University, Auckland, New Zealand. philip.schluter@aut.ac.nz
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Schluter
authors.forename: Avery
authors.initials: A
authors.lastname: Nathens
authors.forename: Melanie L
authors.initials: ML
authors.lastname: Neal
authors.forename: Sandra
authors.initials: S
authors.lastname: Goble
authors.forename: Cate M
authors.initials: CM
authors.lastname: Cameron
authors.forename: Tamzyn M
authors.initials: TM
authors.lastname: Davey
authors.forename: Roderick J
authors.initials: RJ
authors.lastname: McClure
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D006801:Humans; D015601:Injury Severity Score; D016015:Logistic Models; D008390:Markov Chains; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D015599:Trauma Severity Indices; D014481:United States / Q000453:epidemiology; D014947:Wounds and Injuries / Q000145:classification* / Q000453:epidemiology