Predicting six-month mortality of patients with traumatic brain injury: usefulness of common intensive care severity scores

Abstract

IntroductionThe aim of this study was to evaluate the usefulness of the APACHE II (Acute Physiology and Chronic Health Evaluation II), SAPS II (Simplified Acute Physiology Score II) and SOFA (Sequential Organ Failure Assessment) scores compared to simpler models based on age and Glasgow Coma Scale (GCS) in predicting long-term outcome of patients with moderate-to-severe traumatic brain injury (TBI) treated in the intensive care unit (ICU).MethodsA national ICU database was screened for eligible TBI patients (age over 15 years, GCS 3–13) admitted in 2003–2012. Logistic regression was used for customization of APACHE II, SAPS II and SOFA score-based models for six-month mortality prediction. These models were compared to an adjusted SOFA-based model (including age) and a reference model (age and GCS). Internal validation was performed by a randomized split-sample technique. Prognostic performance was determined by assessing discrimination, calibration and precision.ResultsIn total, 1,625 patients were included. The overall six-month mortality was 33%. The APACHE II and SAPS II-based models showed good discrimination (area under the curve (AUC) 0.79, 95% confidence interval (CI) 0.75 to 0.82; and 0.80, 95% CI 0.77 to 0.83, respectively), calibration (P > 0.05) and precision (Brier score 0.166 to 0.167). The SOFA-based model showed poor discrimination (AUC 0.68, 95% CI 0.64 to 0.72) and precision (Brier score 0.201) but good calibration (P > 0.05). The AUC of the SOFA-based model was significantly improved after the insertion of age and GCS (∆AUC +0.11, P < 0.001). The performance of the reference model was comparable to the APACHE II and SAPS II in terms of discrimination (AUC 0.77; compared to APACHE II, ΔAUC −0.02, P = 0.425; compared to SAPS II, ΔAUC −0.03, P = 0.218), calibration (P > 0.05) and precision (Brier score 0.181).ConclusionsA simple prognostic model, based only on age and GCS, displayed a fairly good prognostic performance in predicting six-month mortality of ICU-treated patients with TBI. The use of the more complex scoring systems APACHE II, SAPS II and SOFA added little to the prognostic performance.

Predicting Outcome after Traumatic Brain Injury: Development of Prognostic Scores Based on the IMPACT and the APACHE II

“…Likewise, we recently showed satisfactory discrimination (AUC, 0.79) of the APACHE II for the prediction of 6-month mortality in patients with TBI treated in the ICU. 16 We believe this to be an effect of the APACHE II being originally designed to predict in-hospital mortality, but was, in the current study, used to predict 6-month mortality. This causes the improved outcomes that are achieved over time to be cancelled out by excess mortality after hospital discharge.…”

“…16 This implies that the APACHE II could be used for case-mix adjustment in TBI, as it has in other critically ill patients.…”

Unconscious trauma patients: outcome differences between southern Finland and Germany—lesson learned from trauma-registry comparisons

“…Furthermore, the use of specifically developed prediction models (such as the IMPACT or the CRASH) for patients with TBI should be considered in future TBI benchmarking studies. [17][18][19].…”

Glutamate Neurotransmission in Rodent Models of Traumatic Brain Injury

“…At longer survival times, patients exhibit a decrease in EAAT2 expression, possibly as a result of the activity of intracellular signaling pathways promoting EAAT2 degradation. It is worth noting that shortterm TBI survival is correlated with a higher injury severity 93 ; thus, these findings likely reflect the influence of both of these factors on EAAT2 expression.…”