Classification of comorbidity in trauma: the reliability of pre-injury ASA physical status classification.

Abstract

BACKGROUND:

Pre-injury comorbidities can influence the outcomes of severely injured patients. Pre-injury comorbidity status, graded according to the American Society of Anesthesiologists Physical Status (ASA-PS) classification system, is an independent predictor of survival in trauma patients and is recommended as a comorbidity score in the Utstein Trauma Template for Uniform Reporting of Data. Little is known about the reliability of pre-injury ASA-PS scores. The objective of this study was to examine whether the pre-injury ASA-PS system was a reliable scale for grading comorbidity in trauma patients.

METHODS:

Nineteen Norwegian trauma registry coders were invited to participate in a reliability study in which 50 real but anonymised patient medical records were distributed. Reliability was analysed using quadratic weighted kappa (κ(w)) analysis with 95% CI as the primary outcome measure and unweighted kappa (κ) analysis, which included unknown values, as a secondary outcome measure.

RESULTS:

Fifteen of the invitees responded to the invitation, and ten participated. We found moderate (κ(w)=0.77 [95% CI: 0.64-0.87]) to substantial (κ(w)=0.95 [95% CI: 0.89-0.99]) rater-against-reference standard reliability using κ(w) and fair (κ=0.46 [95% CI: 0.29-0.64]) to substantial (κ=0.83 [95% CI: 0.68-0.94]) reliability using κ. The inter-rater reliability ranged from moderate (κ(w)=0.66 [95% CI: 0.45-0.81]) to substantial (κ(w)=0.96 [95% CI: 0.88-1.00]) for κ(w) and from slight (κ=0.36 [95% CI: 0.21-0.54]) to moderate (κ=0.75 [95% CI: 0.62-0.89]) for κ.

CONCLUSIONS:

The rater-against-reference standard reliability varied from moderate to substantial for the primary outcome measure and from fair to substantial for the secondary outcome measure. The study findings indicate that the pre-injury ASA-PS scale is a reliable score for classifying comorbidity in trauma patients.

• Authors: Kjetil G Ringdal, Nils Oddvar Skaga, Petter Andreas Steen, Morten Hestnes, Petter Laake, J Mary Jones, Hans Morten Lossius
• Journal: Injury (Injury) Vol. 44 Issue 1 Pg. 29-35 (Jan 2013) ISSN: 1879-0267 [Electronic] Netherlands
• PMID: 22277107 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 Elsevier Ltd. All rights reserved.

Topics

• Adult
• Comorbidity
• Female
• Health Status
• Humans
• Injury Severity Score
• Male
• Middle Aged
• Norway (epidemiology)
• Odds Ratio
• Reference Standards
• Registries (standards, statistics & numerical data)
• Reproducibility of Results
• Surveys and Questionnaires
• Wounds and Injuries (diagnosis, epidemiology)