Citation

Cheng K, Bassil R, Carandang R, Hall W, Muehlschlegel S. J. Neurotrauma 2016; 34(8): 1603-1609.

Affiliation

University of Massachusetts Medical School, Departments of Neurology, Anesthesia/Critical Care and Surgery , 55 Lake Ave North , S-5 , Worcester, Massachusetts, United States , 01655 ; susanne.muehlschlegel@umassmemorial.org.

Copyright

(Copyright © 2016, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2016.4657

PMID

27774844

Abstract

The Glasgow Coma Scale (GCS) has limited utility in intubated patients due to the inability to assign verbal sub-scores. The verbal sub-score can be derived from the eye and motor sub-scores using a mathematical model, but the advantage of this method and its use in outcome prognostication in traumatic brain injury (TBI) patients remains unknown. We compared the validated "Core+CT"-IMPACT-model performance in 251 intubated TBI patients prospectively enrolled in the longitudinal OPTIMISM-study between November 2009 and May 2015 when substituting the original motor GCS with the total estimated GCS (teGCS; with estimated verbal sub-score). We hypothesized that model performance would improve with teGCS. Glasgow Outcome Scores were assessed at 3- and 12-months by trained interviewers. In the complete case analysis, there was no statistically or clinically significant difference in the discrimination (C-statistic) at either time-points using the motor GCS vs. teGCS (3-months: 0.893 vs. 0.871;12-months: 0.926 vs. 0.92). At 3-months, IMPACT-model calibration was excellent with motor GCS and teGCS (Hosmer-Lemeshow "goodness-of-fit" Chi-Square p-value 0.9293 and 0.9934), adequate at 12-months with teGCS (0.5893) but low with motor GCS (0.0158), possibly related to diminished power at 12-months. At both time points, motor GCS contributed more to the variability of outcome (Nagelkerke ΔR2) than teGCS (3-months: 5.8% vs. 0.4%; 12-months: 5% vs. 2.6%). The sensitivity analysis with imputed missing outcomes yielded similar results, with improved calibration for both GCS variants. In our cohort of intubated TBI patients, there was no statistically or clinically meaningful improvement in the IMPACT-model performance by substituting the original motor GCS by teGCS.

Language: en