Norwegian survival prediction model in trauma: modelling effects of anatomic injury, acute physiology, age, and co-morbidity

Acta Anaesthesiol Scand. 2014 Mar;58(3):303-15. doi: 10.1111/aas.12256. Epub 2014 Jan 20.


Introduction: Anatomic injury, physiological derangement, age, and injury mechanism are well-founded predictors of trauma outcome. We aimed to develop and validate the first Scandinavian survival prediction model for trauma.

Methods: Eligible were patients admitted to Oslo University Hospital Ullevål within 24 h after injury with Injury Severity Score ≥ 10, proximal penetrating injuries or received by a trauma team. The derivation dataset comprised 5363 patients (August 2000 to July 2006); the validation dataset comprised 2517 patients (August 2006 to July 2008). Exclusion because of missing data was < 1%. Outcome was 30-day mortality. Logistic regression analysis incorporated fractional polynomial modelling and interaction effects. Model validation included a calibration plot, Hosmer-Lemeshow test and receiver operating characteristic (ROC) curves.

Results: The new survival prediction model included the anatomic New Injury Severity Score (NISS), Triage Revised Trauma Score (T-RTS, comprising Glascow Coma Scale score, respiratory rate, and systolic blood pressure), age, pre-injury co-morbidity scored according to the American Society of Anesthesiologists Physical Status Classification System (ASA-PS), and an interaction term. Fractional polynomial analysis supported treating NISS and T-RTS as linear functions and age as cubic. Model discrimination between survivors and non-survivors was excellent. Area (95% confidence interval) under the ROC curve was 0.966 (0.959-0.972) in the derivation and 0.946 (0.930-0.962) in the validation dataset. Overall, low mortality and skewed survival probability distribution invalidated model calibration using the Hosmer-Lemeshow test.

Conclusions: The Norwegian survival prediction model in trauma (NORMIT) is a promising alternative to existing prediction models. External validation of the model in other trauma populations is warranted.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Child
  • Child, Preschool
  • Comorbidity
  • Female
  • Forecasting
  • Glasgow Coma Scale
  • Humans
  • Infant
  • Infant, Newborn
  • Injury Severity Score
  • Male
  • Middle Aged
  • Models, Statistical
  • Norway / epidemiology
  • Reproducibility of Results
  • Survival Analysis
  • Trauma Severity Indices
  • Treatment Outcome
  • Triage
  • Wounds and Injuries / mortality*
  • Wounds and Injuries / pathology*
  • Wounds and Injuries / physiopathology
  • Young Adult