Performance evaluation and validation of the animal trauma triage (ATT) score and modified Glasgow coma scale (mGCS) with suggested category adjustment in dogs – a VetCOT Registry study

Abstract

Objective: To examine the animal trauma triage (ATT) and modified Glasgow coma scare (mGCS) scores as predictors of mortality outcome (death or euthanasia) in injured dogs.

Design: Observational cohort study conducted September 2013 to March 2015 with follow-up until death or hospital discharge Setting: 9 veterinary hospitals including private referral and veterinary teaching hospitals.
Animals: Consecutive sample of 3,599 dogs with complete data entries recruited into the Veterinary Committee on Trauma (VetCOT) patient registry.
Interventions: None

Measurements and Main Results: We compared the predictive power (area under receiver operating characteristic AUROC) and calibration of the ATT and mGCS scores to their components. Overall mortality risk was 7.3% (n=264). Incidence of head trauma was 9.5% (n=341). The ATT score showed a linear relationship with mortality risk. Discriminatory performance of the ATT score was excellent with AUROC=0.92 (95% CI 0.91-0.94), pseudo R2=0.42. Each ATT score increase of 1 point was associated with an increase in mortality odds of 2.07 (95% CI=1.94-2.21 P<0.001). The ‘Eye/Muscle/Integument’ category of the ATT showed poor discrimination (AUROC=0.55). When this component together with the skeletal and cardiac components were omitted from calculation of the overall score, there was no loss in discriminatory capacity (AUROC=0.92 vs 0.91), P=0.09) compared with the full score. The mGCS showed good performance overall, but performance improved when restricted to head trauma patients (AUROC=0.84, 95% CI=0.79-0.90, n=341 vs 0.82 95% CI=0.79-0.85, n=3599). The motor component of the mGCS showed the best predictive performance (AUROC=0.79 vs 0.66/0.69) ,however the full score performed better than the motor component alone (P=0.002). When assessment was restricted to patients with head injury (n=341), the ATT score still performed better than the mGCS (AUROC=0.90 vs 0.84, P=0.04).

Conclusions: In external validation on a large, multi-center dataset, the ATT score showed excellent discrimination and calibration, however a more parsimonious score calculated on only the perfusion, respiratory, and neurological categories showed equivalent performance.

Keywords

Illness severity score; canine; trauma; mortality predictor

Palavras-chave

Escore de gravidade da doença; canino; trauma; preditor de mortalidade