We tested the hypothesis that the motor component of the Glasgow Coma Scale (GCS) conveys most of the predictive information of triage scores (Triage Revised Trauma Score [T-RTS] and the Mechanism, GCS, Age, arterial Pressure score [MGAP]) in trauma patients.

We conducted a multicenter prospective observational study and evaluated 1690 trauma patients in 14 centers. We compared the GCS, T-RTS, MGAP, and Trauma Related Injury Severity Score (reference standard) using the full GCS or its motor component only using logistic regression model, area under the receiver operating characteristic curve, and reclassification technique.

Although some changes were noted for the GCS itself and the Trauma Related Injury Severity Score, no significant change was observed using the motor component only for T-RTS and MGAP when considering (1) the odds ratio of variables included in the logistic model as well as their discrimination and calibration characteristics, (2) the area under the receiver operating characteristic curve (0.827 ± 0.014 vs 0.831 ± 0.014, P = .31 and 0.863 ± 0.011 vs 0.859 ± 0.012, P = .23, respectively), and (3) the reclassification technique. Although the mortality rate remained less than the predetermined threshold of 5% in the low-risk stratum, it slightly increased for MGAP (from 1.9% to 3.9%, P = .048).

The use of the motor component only of the GCS did not change the global performance of triage scores in trauma patients. However, because a subtle increase in mortality rate was observed in the low-risk stratum for MGAP, replacing the GCS by its motor component may not be recommended in every situation.