IMPACT database of traumatic brain injury: design and description

Variability in Standardized Mortality Rates Among Pediatric Traumatic Brain Injury Patients: A Comparative Analysis of Trauma Centers

INTRODUCTION

Traumatic brain injury (TBI) causes significant morbidity and mortality in pediatric patients and care is highly variable. Standardized mortality ratio (SMR) summarizes the mortality rate of a specific center relative to the expected rates across all centers, adjusted for case-mix. This study aimed to evaluate variations in SMRs among pediatric trauma centers for TBI.

METHODS

Patients aged 1-18 diagnosed with TBI within the National Trauma Data Bank (NTDB) from 2017 to 2019 were included. Center-specific SMRs and 95% confidence intervals identified centers with mortality rates significantly better or worse than the median SMR for all centers.

RESULTS

316 centers with 10,598 patients were included. SMRs were risk-adjusted for patient risk factors. Unadjusted mortality ranged from 16.5 to 29.5%. Three centers (1.5%) had significantly better SMR (SMR <1) and three centers (1.5%) had significantly worse SMR (SMR >1). Significantly better centers had a lower proportion of neurosurgical intervention (2.4% vs. 11.8%, p < 0.001), a higher proportion of supplemental oxygen administration (93.7% vs. 83.5%, p = 0.004) and venous thromboembolism prophylaxis (53.2% vs. 40.6%, p < 0.001) compared to significantly worse centers.

CONCLUSIONS

This study identified centers that have significantly higher and lower mortality rates for pediatric TBI patients relative to the overall median rate. These data provide a benchmark for pediatric TBI outcomes and institutional quality improvement.

LEVEL OF EVIDENCE

Level III.

TYPE OF STUDY

Retrospective Comparative Study.

Comparative Analysis of Clinical Severity and Outcomes in Penetrating Versus Blunt Traumatic Brain Injury Propensity Matched Cohorts

Traumatic brain injury (TBI) is a global health challenge; however, penetrating brain injury (PBI) remains under-represented in evidence-based knowledge and research efforts. This study utilized data from the Trauma Quality Improvement Program (TQIP) of the National Trauma Data Bank (NTDB) to investigate outcomes of PBI as compared with clinical-severity-matched non-penetrating or blunt TBI. A total of 1765 patients with PBI were 1:1 propensity score-matched for clinical severity with blunt TBI patients. The intent of PBI was self-inflicted in 34.1% of the cases, and the mechanism was firearm-inflicted in 89.1%. Mortality was found to be significantly more common in PBI than in the severity- matched TBI cohort (33.9% vs. 14.3 %, p < 0.001) as was unfavorable outcome. Mortality was mediated by withdrawal of life-sustaining therapies (WOLST) 30% of the time, and WOLST occurred earlier (median 3 days vs. 6 days, p < 0.001) in PBI. Increased rate of mortality was observed with a Glasgow Coma Scale (GCS) of <11 in PBI as compared with <7 in blunt TBI. In conclusion, PBI patients exhibited higher mortality rates and unfavorable outcomes; one third of excess mortality was mediated by WOLST. The study also brings into question the applicability of the conventional TBI classification, based on GCS, in PBI. We emphasize the need to address the observed disparities and better understand the distinctive characteristics and mechanisms underlying PBI outcomes to improve patient care and reduce mortality.

Impact of Automated Prognostication on Traumatic Brain Injury Care: A Focus Group Study

BACKGROUND

Prognosticating outcomes for traumatic brain injury (TBI) patients is challenging due to the required specialized skills and variability among clinicians. Recent attempts to standardize TBI prognosis have leveraged machine learning (ML) methodologies. This study evaluates the necessity and influence of ML-assisted TBI prognostication through healthcare professionals' perspectives via focus group discussions.

METHODS

Two virtual focus groups included ten key TBI care stakeholders (one neurosurgeon, two emergency clinicians, one internist, two radiologists, one registered nurse, two researchers in ML and healthcare and one patient representative). They answered six open-ended questions about their perceptions and potential ML use in TBI prognostication. Transcribed focus group discussions were thematically analyzed using qualitative data analysis software.

RESULTS

The study captured diverse perceptions and interests in TBI prognostication across clinical specialties. Notably, certain clinicians who currently do not prognosticate expressed an interest in doing so independently provided they had access to ML support. Concerns included ML's accuracy and the need for proficient ML researchers in clinical settings. The consensus suggested using ML as a secondary consultation tool and promoting collaboration with internal or external research resources. Participants believed ML prognostication could enhance disposition planning and standardize care regardless of clinician expertise or injury severity. There was no evidence of perceived bias or interference during the discussions.

CONCLUSION

Our findings revealed an overall positive attitude toward ML-based prognostication. Despite raising multiple concerns, the focus group discussions were particularly valuable in underscoring the potential of ML in democratizing and standardizing TBI prognosis practices.

Early systemic insults following traumatic brain injury: association with biomarker profiles, therapy for intracranial hypertension, and neurological outcomes-an analysis of CENTER-TBI data

PURPOSE

We analysed the impact of early systemic insults (hypoxemia and hypotension, SIs) on brain injury biomarker profiles, acute care requirements during intensive care unit (ICU) stay, and 6-month outcomes in patients with traumatic brain injury (TBI).

METHODS

From patients recruited to the Collaborative European neurotrauma effectiveness research in TBI (CENTER-TBI) study, we documented the prevalence and risk factors for SIs and analysed their effect on the levels of brain injury biomarkers [S100 calcium-binding protein B (S100B), neuron-specific enolase (NSE), neurofilament light (NfL), glial fibrillary acidic protein (GFAP), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), and protein Tau], critical care needs, and 6-month outcomes [Glasgow Outcome Scale Extended (GOSE)].

RESULTS

Among 1695 TBI patients, 24.5% had SIs: 16.1% had hypoxemia, 15.2% had hypotension, and 6.8% had both. Biomarkers differed by SI category, with higher S100B, Tau, UCH-L1, NSE and NfL values in patients with hypotension or both SIs. The ratio of neural to glial injury (quantified as UCH-L1/GFAP and Tau/GFAP ratios) was higher in patients with hypotension than in those with no SIs or hypoxia alone. At 6 months, 380 patients died (22%), and 759 (45%) had GOSE ≤ 4. Patients who experienced at least one SI had higher mortality than those who did not (31.8% vs. 19%, p < 0.001).

CONCLUSION

Though less frequent than previously described, SIs in TBI patients are associated with higher release of neuronal than glial injury biomarkers and with increased requirements for ICU therapies aimed at reducing intracranial hypertension. Hypotension or combined SIs are significantly associated with adverse 6-month outcomes. Current criteria for hypotension may lead to higher biomarker levels and more negative outcomes than those for hypoxemia suggesting a need to revisit pressure targets in the prehospital settings.

Improvement in Functional Outcome from 6 to 12 Months After Moderate and Severe Traumatic Brain Injury Is Frequent, But May Not Be Detected With the Glasgow Outcome Scale Extended

The aims of this study were (1) to report outcome and change in outcome in patients with moderate and severe traumatic brain injury (mo/sTBI) between 6 and 12 months post-injury as measured by the Glasgow Outcome Scale Extended (GOSE), (2) to explore if demographic/injury-related variables can predict improvement in GOSE score, and (3) to investigate rate of improvement in Disability Rating Scale (DRS) score, in patients with a stable GOSE. All surviving patients ≥16 years of age who were admitted with mo/sTBI (Glasgow Coma Scale [GCS] score ≤13) to the regional trauma center in Central Norway between 2004 and 2019 were prospectively included (n = 439 out of 503 eligible). GOSE and DRS were used to assess outcome. Twelve-months post-injury, 13% with moTBI had severe disability (GOSE 2-4) versus 27% in sTBI, 26% had moderate disability (GOSE 5-6) versus 41% in sTBI and 62% had good recovery (GOSE 7-8) versus 31% in sTBI. From 6 to 12 months post-injury, 27% with moTBI and 32% with sTBI had an improvement, whereas 6% with moTBI and 6% with sTBI had a deterioration in GOSE score. Younger age and higher GCS score were associated with improved GOSE score. Improvement was least frequent for patients with a GOSE score of 3 at 6 months. In patients with a stable GOSE score of 3, an improvement in DRS score was observed in 22 (46%) patients. In conclusion, two thirds and one third of patients with mo/sTBI, respectively, had a good recovery. Importantly, change, mostly improvement, in GOSE score between 6 and 12 months was frequent and argues against the use of 6 months outcome as a time end-point in research. The GOSE does, however, not seem to be sensitive to actual change in function in the lower categories and a combination of outcome measures may be needed to describe the consequences after TBI.

Pupillary dynamics predict long-term outcome in a cohort of acute traumatic brain injury coma patients

OBJECTIVE

Examining the size and reactivity of the pupils of traumatic brain injury coma patients is fundamental in the Neuro-intensive care unit (ICU). Pupil parameters on admission predict long-term clinical outcomes. However, little is known about the dynamics of pupillary parameters and their potential value for outcome prediction.

METHODS

This study applied a time-course analysis of pupillary signals (size and photo-reactivity) in acute traumatic brain injury coma patients (n = 20) to predict outcome at 6 months.

RESULTS

The time course of pupillary signals was informative in discriminating favorable (F) versus unfavorable (U) outcomes, with the highest correlation within the 1st week notwithstanding pharmacological sedation. Patients with favorable outcome at 6 months showed more consistent in time isochoric and photo-reactive pupils. In contrast, patients with an unfavorable outcome showed more variable measures that tended to stabilize toward pathological values.

INTERPRETATION

Time-dependent tracking of pupils' size and reactivity is a promising application for ICU monitoring and long-term prognosis. These findings support the usefulness of automatic tools for the dynamic, quantitative, and objective measurements of pupils.

Mortality of Surgically Treated Neurotrauma in Elderly Patients and the Development of a Prediction Score: Geriatric Neurotrauma Mortality Score

BACKGROUND

As the population worldwide is aging, the need for surgery in elderly patients with neurotrauma is increasing. The aim of this study was to compare the outcome of elderly patients undergoing surgery for neurotrauma with younger patients and to identify the risk factors for mortality.

METHODS

We retrospectively analyzed consecutive patients undergoing craniotomy or craniectomy for neurotrauma at our institution from 2012 to 2019. Patients were divided into two groups (≥70 years or <70 years) and compared. The primary outcome was the 30-day mortality rate. Potential risk factors for 30-day mortality were assessed in a uni- and multivariate regression model for both age groups, forming the basis of a 30-day mortality prediction score.

RESULTS

We included 163 consecutive patients (average age 57.98 ± 19.87 years); 54 patients were ≥70 years. Patients ≥70 years showed a significantly better median preoperative Glasgow Coma Scale (GCS) score compared with young patients (P < 0.001), and fewer pupil asymmetry (P = 0.001), despite having a higher Marshall score (P = 0.07) at admission. Multivariate regression analysis identified low pre- and postoperative GCS scores and the lack of prompt postoperative prophylactic low-molecular-weight heparin treatment as risk factors for 30-day mortality. Our score showed moderate accuracy in predicting 30-day mortality with an area under the curve of 0.76.

CONCLUSIONS

Elderly patients after neurotrauma present with a better GCS at admission despite having more severe radiographic injuries. Mortality and favorable outcome rates are comparable between the age groups.

External validation of the Glasgow coma scale-pupils in low- to middle-income country patients with traumatic brain injury: Could “motor score-pupil” have higher prognostic value?

Background:

The objective of this study is to validate the admission Glasgow coma scale (GCS) associated with pupil response (GCS-P) to predict traumatic brain injury (TBI) patient’s outcomes in a low- to middle-income country and to compare its performance with that of a simplified model combining the better motor response of the GCS and the pupilar response (MS-P).

Methods:

This is a prospective cohort of patients with TBI in a tertiary trauma reference center in Brazil. Predictive values of the GCS, GCS-P, and MS-P were evaluated and compared for 14 day and in-hospital mortality outcomes and length of hospital stay (LHS).

Results:

The study enrolled 447 patients. MS-P demonstrated better discriminative ability than GCS to predict mortality (AUC 0.736 × 0.658; P < 0.001) and higher AUC than GCS-P (0.736 × 0.704, respectively; P = 0.073). For hospital mortality, MS-P demonstrated better discrimination than GCS (AUC, 0.750 × 0.682; P < 0.001) and higher AUC than GCS-P (0.750 × 0.714; P = 0.027). Both scores were good predictors of LHS (r2 = 0.084 [GCS-P] × 0.079 [GCS] × 0.072 [MS-P]).

Conclusion:

The predictive value of the GCS, GCS-P, and MS-P scales was demonstrated, thus contributing to its external validation in low- to middle-income country.

Predicting Clinical Outcomes 7-10 Years after Severe Traumatic Brain Injury: Exploring the Prognostic Utility of the IMPACT Lab Model and Cerebrospinal Fluid UCH-L1 and MAP-2

BACKGROUND

Severe traumatic brain injury (TBI) is a major contributor to disability and mortality in the industrialized world. Outcomes of severe TBI are profoundly heterogeneous, complicating outcome prognostication. Several prognostic models have been validated for acute prediction of 6-month global outcomes following TBI (e.g., morbidity/mortality). In this preliminary observational prognostic study, we assess the utility of the International Mission on Prognosis and Analysis of Clinical Trials in TBI (IMPACT) Lab model in predicting longer term global and cognitive outcomes (7-10 years post injury) and the extent to which cerebrospinal fluid (CSF) biomarkers enhance outcome prediction.

METHODS

Very long-term global outcome was assessed in a total of 59 participants (41 of whom did not survive their injuries) using the Glasgow Outcome Scale-Extended and Disability Rating Scale. More detailed outcome information regarding cognitive functioning in daily life was collected from 18 participants surviving to 7-10 years post injury using the Cognitive Subscale of the Functional Independence Measure. A subset (n = 10) of these participants also completed performance-based cognitive testing (Digit Span Test) by telephone. The IMPACT lab model was applied to determine its prognostic value in relation to very long-term outcomes as well as the additive effects of acute CSF ubiquitin C-terminal hydrolase-L1 (UCH-L1) and microtubule associated protein 2 (MAP-2) concentrations.

RESULTS

The IMPACT lab model discriminated favorable versus unfavorable 7- to 10-year outcome with an area under the receiver operating characteristic curve of 0.80. Higher IMPACT lab model risk scores predicted greater extent of very long-term morbidity (β = 0.488 p = 0.000) as well as reduced cognitive independence (β =  - 0.515, p = 0.034). Acute elevations in UCH-L1 levels were also predictive of lesser independence in cognitive activities in daily life at very long-term follow-up (β = 0.286, p = 0.048). Addition of two CSF biomarkers significantly improved prediction of very long-term neuropsychological performance among survivors, with the overall model (including IMPACT lab score, UCH-L1, and MAP-2) explaining 89.6% of variance in cognitive performance 7-10 years post injury (p = 0.008). Higher acute UCH-L1 concentrations were predictive of poorer cognitive performance (β =  - 0.496, p = 0.029), whereas higher acute MAP-2 concentrations demonstrated a strong cognitive protective effect (β = 0.679, p = 0.010).

CONCLUSIONS

Although preliminary, results suggest that existing prognostic models, including models with incorporation of CSF markers, may be applied to predict outcome of severe TBI years after injury. Continued research is needed examining early predictors of longer-term outcomes following TBI to identify potential targets for clinical trials that could impact long-ranging functional and cognitive outcomes.

Harmonization-Information Trade-Offs for Sharing Individual Participant Data in Biomedicine

Biomedical practice is evidence-based. Peer-reviewed papers are the primary medium to present evidence and data-supported results to drive clinical practice. However, it could be argued that scientific literature does not contain data, but rather narratives about and summaries of data. Meta-analyses of published literature may produce biased conclusions due to the lack of transparency in data collection, publication bias, and inaccessibility to the data underlying a publication ('dark data'). Co-analysis of pooled data at the level of individual research participants can offer higher levels of evidence, but this requires that researchers share raw individual participant data (IPD). FAIR (findable, accessible, interoperable, and reusable) data governance principles aim to guide data lifecycle management by providing a framework for actionable data sharing. Here we discuss the implications of FAIR for data harmonization, an essential step for pooling data for IPD analysis. We describe the harmonization-information trade-off, which states that the level of granularity in harmonizing data determines the amount of information lost. Finally, we discuss a framework for managing the trade-off and the levels of harmonization. In the coming era of funder mandates for data sharing, research communities that effectively manage data harmonization will be empowered to harness big data and advanced analytics such as machine learning and artificial intelligence tools, leading to stunning new discoveries that augment our understanding of diseases and their treatments. By elevating scientific data to the status of a first-class citizen of the scientific enterprise, there is strong potential for biomedicine to transition from a narrative publication product orientation to a modern data-driven enterprise where data itself is viewed as a primary work product of biomedical research.

Instrumental variable analysis to estimate treatment effects: a simulation study showing potential benefits of conditioning on hospital

Background

Instrumental variable (IV) analysis holds the potential to estimate treatment effects from observational data. IV analysis potentially circumvents unmeasured confounding but makes a number of assumptions, such as that the IV shares no common cause with the outcome. When using treatment preference as an instrument, a common cause, such as a preference regarding related treatments, may exist. We aimed to explore the validity and precision of a variant of IV analysis where we additionally adjust for the provider: adjusted IV analysis.

Methods

A treatment effect on an ordinal outcome was simulated (beta − 0.5 in logistic regression) for 15.000 patients, based on a large data set (the IMPACT data, n = 8799) using different scenarios including measured and unmeasured confounders, and a common cause of IV and outcome. We compared estimated treatment effects with patient-level adjustment for confounders, IV with treatment preference as the instrument, and adjusted IV, with hospital added as a fixed effect in the regression models.

Results

The use of patient-level adjustment resulted in biased estimates for all the analyses that included unmeasured confounders, IV analysis was less confounded, but also less reliable. With correlation between treatment preference and hospital characteristics (a common cause) estimates were skewed for regular IV analysis, but not for adjusted IV analysis.

Conclusion

When using IV analysis for comparing hospitals, some limitations of regular IV analysis can be overcome by adjusting for a common cause.

Trial registration

We do not report the results of a health care intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01598-6.

A Precision Medicine Agenda in Traumatic Brain Injury

Traumatic brain injury remains a leading cause of death and disability across the globe. Substantial uncertainty in outcome prediction continues to be the rule notwithstanding the existing prediction models. Additionally, despite very promising preclinical data, randomized clinical trials (RCTs) of neuroprotective strategies in moderate and severe TBI have failed to demonstrate significant treatment effects. Better predictive models are needed, as the existing validated ones are more useful in prognosticating poor outcome and do not include biomarkers, genomics, proteonomics, metabolomics, etc. Invasive neuromonitoring long believed to be a "game changer" in the care of TBI patients have shown mixed results, and the level of evidence to support its widespread use remains insufficient. This is due in part to the extremely heterogenous nature of the disease regarding its etiology, pathology and severity. Currently, the diagnosis of traumatic brain injury (TBI) in the acute setting is centered on neurological examination and neuroimaging tools such as CT scanning and MRI, and its treatment has been largely confronted using a "one-size-fits-all" approach, that has left us with many unanswered questions. Precision medicine is an innovative approach for TBI treatment that considers individual variability in genes, environment, and lifestyle and has expanded across the medical fields. In this article, we briefly explore the field of precision medicine in TBI including biomarkers for therapeutic decision-making, multimodal neuromonitoring, and genomics.

A role for insulin-like growth factor-1 in hippocampal plasticity following traumatic brain injury

Traumatic brain injury (TBI) initiates a constellation of secondary injury cascades, leading to neuronal damage and dysfunction that is often beyond the scope of endogenous repair mechanisms. Cognitive deficits are among the most persistent morbidities resulting from TBI, necessitating a greater understanding of mechanisms of posttraumatic hippocampal damage and neuroplasticity and identification of therapies that improve recovery by enhancing repair pathways. Focusing here on hippocampal neuropathology associated with contusion-type TBIs, the impact of brain trauma on synaptic structure and function and the process of adult neurogenesis is discussed, reviewing initial patterns of damage as well as evidence for spontaneous recovery. A case is made that insulin-like growth factor-1 (IGF-1), a growth-promoting peptide synthesized in both the brain and the periphery, is well suited to augment neuroplasticity in the injured brain. Essential during brain development, multiple lines of evidence delineate roles in the adult brain for IGF-1 in the maintenance of synapses, regulation of neurotransmission, and modulation of forms of synaptic plasticity such as long-term potentiation. Further, IGF-1 enhances adult hippocampal neurogenesis though effects on proliferation and neuronal differentiation of neural progenitor cells and on dendritic growth of newly born neurons. Post-injury administration of IGF-1 has been effective in rodent models of TBI in improving learning and memory, attenuating death of mature hippocampal neurons and promoting neurogenesis, providing critical proof-of-concept data. More studies are needed to explore the effects of IGF-1-based therapies on synaptogenesis and synaptic plasticity following TBI and to optimize strategies in order to stimulate only appropriate, functional neuroplasticity.

Excavating FAIR Data: the Case of the Multicenter Animal Spinal Cord Injury Study (MASCIS), Blood Pressure, and Neuro-Recovery

Meta-analyses suggest that the published literature represents only a small minority of the total data collected in biomedical research, with most becoming 'dark data' unreported in the literature. Dark data is due to publication bias toward novel results that confirm investigator hypotheses and omission of data that do not. Publication bias contributes to scientific irreproducibility and failures in bench-to-bedside translation. Sharing dark data by making it Findable, Accessible, Interoperable, and Reusable (FAIR) may reduce the burden of irreproducible science by increasing transparency and support data-driven discoveries beyond the lifecycle of the original study. We illustrate feasibility of dark data sharing by recovering original raw data from the Multicenter Animal Spinal Cord Injury Study (MASCIS), an NIH-funded multi-site preclinical drug trial conducted in the 1990s that tested efficacy of several therapies after a spinal cord injury (SCI). The original drug treatments did not produce clear positive results and MASCIS data were stored in boxes for more than two decades. The goal of the present study was to independently confirm published machine learning findings that perioperative blood pressure is a major predictor of SCI neuromotor outcome (Nielson et al., 2015). We recovered, digitized, and curated the data from 1125 rats from MASCIS. Analyses indicated that high perioperative blood pressure at the time of SCI is associated with poorer health and worse neuromotor outcomes in more severe SCI, whereas low perioperative blood pressure is associated with poorer health and worse neuromotor outcome in moderate SCI. These findings confirm and expand prior results that a narrow window of blood-pressure control optimizes outcome, and demonstrate the value of recovering dark data for assessing reproducibility of findings with implications for precision therapeutic approaches.

Evolution and Impact of the Brain Trauma Foundation Guidelines

The Brain Trauma Foundation (BTF) Guidelines for the Management of Severe Head Injury were the first clinical practice guidelines published by any surgical specialty. These guidelines have earned a reputation for rigor and have been widely adopted around the world. Implementation of these guidelines has been associated with a 50% reduction in mortality and reduced costs of patient care. Over their 25-yr history the traumatic brain injury (TBI) guidelines have been expanded, refined, and made increasingly more rigorous in conjunction with new clinical evidence and evolving methodologic standards. Here, we discuss the history and accomplishments of BTF guidelines for TBI as well as their limitations. We also discuss planned changes to future TBI guidelines intended to increase their utility and positive impact in an evolving medical landscape. Perhaps the greatest limitation of TBI guidelines now is the lack of high-quality clinical research as well as novel diagnostics and treatments with which to generate substantially new recommendations.

Questionnaires vs Interviews for the Assessment of Global Functional Outcomes After Traumatic Brain Injury

IMPORTANCE

An interview is considered the gold standard method of assessing global functional outcomes in clinical trials among patients with acute traumatic brain injury (TBI). However, several multicenter clinical trials have used questionnaires completed by a patient or caregiver to assess the primary end point.

OBJECTIVE

To examine agreement between interview and questionnaire formats for assessing TBI outcomes and to consider whether an interview has advantages.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from patients enrolled in the Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) project from December 2014 to December 2017. Data were analyzed from December 2020 to April 2021. Included patients were aged 16 years or older with TBI and a clinical indication for computed tomography imaging. Outcome assessments were completed using both an interview and a questionnaire at follow-up 3 and 6 months after injury.

EXPOSURES

Traumatic brain injury of all severities.

MAIN OUTCOMES AND MEASURES

Ratings on the Glasgow Outcome Scale-Extended (GOSE) administered as a structured interview rated by an investigator and as a questionnaire completed by patients or caregivers and scored centrally were compared, and the strength of agreement was evaluated using weighted κ statistics. Secondary outcomes included comparison of different sections of the GOSE assessments and the association of GOSE ratings with baseline factors and patient-reported mental health, health-related quality of life, and TBI symptoms.

RESULTS

Among the 3691 eligible individuals in the CENTER-TBI study, both GOSE assessment formats (interview and questionnaire) were completed by 994 individuals (26.9%) at 3 months after TBI (654 [65.8%] male; median age, 53 years [IQR, 33-66 years]) and 628 (17.0%) at 6 months (409 [65.1%] male; median age, 51 years [IQR, 31-64 years]). Outcomes of the 2 assessment methods agreed well at both 3 months (weighted κ, 0.77; 95% CI, 0.73-0.80) and 6 months (weighted κ, 0.82; 95% CI, 0.78-0.86). Furthermore, item-level agreement between the 2 methods was good for sections regarding independence in everyday activities (κ, 0.70-0.79 across both time points) and moderate for sections regarding subjective aspects of functioning such as relationships and symptoms (κ, 0.41-0.51 across both time points). Compared with questionnaires, interviews recorded more problems with work (294 [30.5%] vs 233 [24.2%] at 3 months and 161 [26.8%] vs 136 [22.7%] at 6 months), fewer limitations in social and leisure activities (330 [33.8%] vs 431 [44.1%] at 3 months and 179 [29.7%] vs 219 [36.4%] at 6 months), and more symptoms (524 [53.6%] vs 324 [33.1%] at 3 months and 291 [48.4%] vs 179 [29.8%] at 6 months). Interviewers sometimes assigned an overall rating based on judgment rather than interview scoring rules, particularly for patients with potentially unfavorable TBI outcomes. However, for both formats, correlations with baseline factors (ρ, -0.13 to 0.42) and patient-reported outcomes (ρ, 0.29 to 0.65) were similar in strength.

CONCLUSIONS AND RELEVANCE

In this cohort study, GOSE ratings obtained by questionnaire and interview methods were in good agreement. The similarity of associations of the ratings obtained by both GOSE methods with baseline factors and other TBI outcome measures suggests that despite some apparent differences, the core information collected by both interviews and questionnaires was similar. The findings support the use of questionnaires in studies in which this form of contact may offer substantial practical advantages compared with interviews.

Prediction of Outcome Based on Trauma and Injury Severity Score, IMPACT and CRASH Prognostic Models in Moderate-to-Severe Traumatic Brain Injury in the Elderly

Objectives:

This study aimed to evaluate the trauma and injury severity score (TRISS), IMPACT (international mission for prognosis and analysis of clinical trials), and CRASH (corticosteroid randomization after significant head injury) prognostic models for prediction of outcome after moderate-to-severe traumatic brain injury (TBI) in the elderly following road traffic accident.

Design:

This was a prospective observational study.

Materials and Methods:

This was a prospective observational study on 104 elderly trauma patients who were admitted to tertiary care hospital, over a consecutive period of 18 months from December 2016 to May 2018. On the day of admission, data were collected from each patient to compute the TRISS, IMPACT, and CRASH and outcome evaluation was prospectively done at discharge, 14^th day, and 6-month follow-up.

Results:

This study included 104 TBI patients with a mean age of 66.75 years and with a mortality rate of 32% and 45%, respectively, at discharge and at the end of 6 months. The predictive accuracies of the TRISS, CRASH (computed tomography), and IMPACT (core, extended, laboratory) were calculated using receiver operator characteristic (ROC) curves for the prediction of mortality. Best cutoff point for predicting mortality in elderly TBI patients using TRISS system was a score of ≤88 (sensitivity 94%, specificity of 80%, and area under ROC curve 0.95), similarly cutoff point under the CRASH at 14 days was score of >35 (100%, 80%, 0.958); for CRASH at 6 months, best cutoff point was at >84 (88%, 88%, 0.959); for IMPACT (core), it was >38 (88%, 93%, 0.976); for IMPACT (extended), it was >27 (91%, 89%, 0.968); and for IMPACT (lab), it was >41 (82%, 100%, 0.954). There were statistical differences among TRISS, CRASH (at 14 days and 6 months), and IMPACT (core, extended, lab) in terms of area under the ROC curve (P < 0.0001).

Conclusion:

IMPACT (core, extended) models were the strongest predictors of mortality in moderate-to-severe TBI when compared with the TRISS, CRASH, and IMPACT (lab) models.

Proper Partial Pressure of Arterial Oxygen for Patients with Traumatic Brain Injury

Background

The partial pressure of arterial oxygen (PaO₂) is critical to the outcome of patients with traumatic brain injury (TBI). However, it is not clear what range of PaO₂ should be maintained to improve patient outcome. The aim of this study was to explore the PaO₂ value needed in the acute phase of TBI and provide new evidence for clinical practice.

Material/Methods

A total of 153 patients with TBI were enrolled retrospectively. Univariate and multivariate logistic regression analyses were conducted on sex, Glasgow Coma Scale (GCS) score on admission, PaO₂ within 6 h of admission, oxygenation index, and other factors. The Glasgow Outcome Score (GOS) of the patient at discharge was used as an indicator of outcome. The good outcome group had GOS ≥4, and the poor outcome group had GOS <4.

Results

The 153 patients were divided into a good outcome group (n=62) and poor outcome group (n=91). There was a significant difference in sex, admission GCS, surgery, airway status, PaO₂, and oxygen index within 6 h of admission between the 2 groups. Logistic regression analysis showed that PaO₂ <60 mmHg, male sex, and admission GCS score of 3 to 12 were independent risk factors for a poor outcome.

Conclusions

Patients with TBI having PaO₂ <60 mmHg within 6 h after admission were more likely to have poor outcomes. The upper limit value of PaO₂ that affects the outcome of TBI in patients has not been found.

Contribution of CT-Scan Analysis by Artificial Intelligence to the Clinical Care of TBI Patients

The gold standard to diagnose intracerebral lesions after traumatic brain injury (TBI) is computed tomography (CT) scan, and due to its accessibility and improved quality of images, the global burden of CT scan for TBI patients is increasing. The recent developments of automated determination of traumatic brain lesions and medical-decision process using artificial intelligence (AI) represent opportunities to help clinicians in screening more patients, identifying the nature and volume of lesions and estimating the patient outcome. This short review will summarize what is ongoing with the use of AI and CT scan for patients with TBI.

Clinical, Surgical and Outcome Predictive Factor Analysis of Operated Acute Subdural Hematoma Cases: A Retrospective Study of 114 Operated Cases at Tertiary Centre

Objective To analyze clinical, surgical and outcome predictive factors of operated acute subdural hematoma (SDH) cases for prognostication and surgical outcome prediction.

Material and Methods This retrospective study includes 114 patients operated for acute SDH in the Department of Neurosurgery of IMS BHU, Varanasi, India, a tertiary care center, between 1 August 2018 and 1 November 2019. Each patient was evaluated for age, sex, mode of injury, localization of hematoma, clinical presentation, comorbidity, severity of injury, best motor response, CT findings, and Glasgow outcome scale (GOS) at discharge. The outcome was also evaluated by further making a dichotomized group using GOS in death/dependent (1–3) versus independent (4–5). Statistical tests were done using the GraphPad Prism version 8.3.0.

Results The most common age group operated upon in this study was the 40 to 60 years age group (n = 45, 39.48%). Males were 78% with male to female ratio of 3.56:1. The most common clinical presentation was altered sensorium (98.25%). The most common comorbidity was hypertension (n = 32, 28.07%). GCS at admission, severity of injury, pupillary changes, and best motor response (p < 0.0001) were significantly associated with surgical outcome.

Conclusion GCS at admission, severity of injury, pupillary changes, and best motor response were significantly (p < 0.05) associated with surgical outcome. Age and gender of patients were not found to be significantly associated.

Differential neuropathology and functional outcome after equivalent traumatic brain injury in aged versus young adult mice

The CDC estimate that nearly 3 million Americans sustain a traumatic brain injury (TBI) each year. Even when medical comorbidities are accounted for, age is an independent risk factor for poor outcome after TBI. Nonetheless, few studies have examined the pathophysiology of age-linked biologic outcomes in TBI. We hypothesized that aged mice would demonstrate more severe neuropathology and greater functional deficits as compared to young adult mice after equivalent traumatic brain injuries. Young adult (14-week-old) and aged (80-week-old) C57BL/6 male mice underwent an open-head controlled cortical impact to induce TBI or a sham injury. At 30-days post-injury groups underwent behavioral phenotyping, magnetic resonance imaging, and histologic analyses. Contrary to our hypothesis, young adult TBI mice exhibited more severe neuropathology and greater loss of white matter connectivity as compared to aged mice after TBI. These findings correlated to differential functional outcomes in anxiety response, learning, and memory between young adult and aged mice after TBI. Although the mechanisms underlying this age-effect remain unclear, attenuated signs of secondary brain injury in aged TBI mice point towards different inflammatory and repair processes between age groups. These data suggest that age may need to be an a priori consideration in future clinical trial design.

Predicting negative health outcomes in older general practice patients with chronic illness: Rationale and development of the PROPERmed harmonized individual participant data database

The prevalence of multimorbidity and polypharmacy increases significantly with age and are associated with negative health consequences. However, most current interventions to optimize medication have failed to show significant effects on patient-relevant outcomes. This may be due to ineffectiveness of interventions themselves but may also reflect other factors: insufficient sample sizes, heterogeneity of population. To address this issue, the international PROPERmed collaboration was set up to obtain/synthesize individual participant data (IPD) from five cluster-randomized trials. The trials took place in Germany and The Netherlands and aimed to optimize medication in older general practice patients with chronic illness. PROPERmed is the first database of IPD to be drawn from multiple trials in this patient population and setting. It offers the opportunity to derive prognostic models with increased statistical power for prediction of patient-relevant outcomes resulting from the interplay of multimorbidity and polypharmacy. This may help patients from this heterogeneous group to be stratified according to risk and enable clinicians to identify patients that are likely to benefit most from resource/time-intensive interventions. The aim of this manuscript is to describe the rationale behind PROPERmed collaboration, characteristics of the included studies/participants, development of the harmonized IPD database and challenges faced during this process.

Ordinal outcome analysis improves the detection of between-hospital differences in outcome

Background

There is a growing interest in assessment of the quality of hospital care, based on outcome measures. Many quality of care comparisons rely on binary outcomes, for example mortality rates. Due to low numbers, the observed differences in outcome are partly subject to chance. We aimed to quantify the gain in efficiency by ordinal instead of binary outcome analyses for hospital comparisons. We analyzed patients with traumatic brain injury (TBI) and stroke as examples.

Methods

We sampled patients from two trials. We simulated ordinal and dichotomous outcomes based on the modified Rankin Scale (stroke) and Glasgow Outcome Scale (TBI) in scenarios with and without true differences between hospitals in outcome. The potential efficiency gain of ordinal outcomes, analyzed with ordinal logistic regression, compared to dichotomous outcomes, analyzed with binary logistic regression was expressed as the possible reduction in sample size while keeping the same statistical power to detect outliers.

Results

In the IMPACT study (9578 patients in 265 hospitals, mean number of patients per hospital = 36), the analysis of the ordinal scale rather than the dichotomized scale (‘unfavorable outcome’), allowed for up to 32% less patients in the analysis without a loss of power. In the PRACTISE trial (1657 patients in 12 hospitals, mean number of patients per hospital = 138), ordinal analysis allowed for 13% less patients. Compared to mortality, ordinal outcome analyses allowed for up to 37 to 63% less patients.

Conclusions

Ordinal analyses provide the statistical power of substantially larger studies which have been analyzed with dichotomization of endpoints. We advise to exploit ordinal outcome measures for hospital comparisons, in order to increase efficiency in quality of care measurements.

Trial registration

We do not report the results of a health care intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-020-01185-7.

Outcome Prediction after Moderate and Severe Traumatic Brain Injury: External Validation of Two Established Prognostic Models in 1742 European Patients

The International Mission on Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (IMPACT) and Corticoid Randomisation After Significant Head injury (CRASH) prognostic models predict functional outcome after moderate and severe traumatic brain injury (TBI). We aimed to assess their performance in a contemporary cohort of patients across Europe. The Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) core study is a prospective, observational cohort study in patients presenting with TBI and an indication for brain computed tomography. The CENTER-TBI core cohort consists of 4509 TBI patients available for analyses from 59 centers in 18 countries across Europe and Israel. The IMPACT validation cohort included 1173 patients with GCS ≤12, age ≥14, and 6-month Glasgow Outcome Scale-Extended (GOSE) available. The CRASH validation cohort contained 1742 patients with GCS ≤14, age ≥16, and 14-day mortality or 6-month GOSE available. Performance of the three IMPACT and two CRASH model variants was assessed with discrimination (area under the receiver operating characteristic curve; AUC) and calibration (comparison of observed vs. predicted outcome rates). For IMPACT, model discrimination was good, with AUCs ranging between 0.77 and 0.85 in 1173 patients and between 0.80 and 0.88 in the broader CRASH selection (n = 1742). For CRASH, AUCs ranged between 0.82 and 0.88 in 1742 patients and between 0.66 and 0.80 in the stricter IMPACT selection (n = 1173). Calibration of the IMPACT and CRASH models was generally moderate, with calibration-in-the-large and calibration slopes ranging between -2.02 and 0.61 and between 0.48 and 1.39, respectively. The IMPACT and CRASH models adequately identify patients at high risk for mortality or unfavorable outcome, which supports their use in research settings and for benchmarking in the context of quality-of-care assessment.

Establishment and validation of a model for brain injury state evaluation and prognosis prediction

PURPOSE

Traumatic brain injury (TBI) is one of the leading causes of disability and death in modern times, whose evaluation and prognosis prediction have been one of the most critical issues in TBI management. However, the existed models for the abovementioned purposes were defective to varying degrees. This study aims to establish an ideal brain injury state clinical prediction model (BISCPM).

METHODS

This study was a retrospective design. The six-month outcomes of patients were selected as the end point event. BISCPM was established by using the split-sample technology, and externally validated via different tests of comparison between the observed and predicted six-month mortality in validating group. TBI patients admitted from July 2006 to June 2012 were recruited and randomly divided into establishing model group and validating model group. Twenty-one scoring indicators were included in BISCPM and divided into three parts, A, B, and C. Part A included movement, pupillary reflex and diameter, CT parameters, and secondary brain insult factors, etc. Part B was age and part C was medical history of the patients. The total score of part A, B and C was final score of BISCPM.

RESULTS

Altogether 1156 TBI patients were included with 578 cases in each group. The score of BISCPM from validating group ranged from 2.75 to 31.94, averaging 13.64 ± 5.59. There was not statistical difference between observed and predicted mortality for validating group. The discrimination validation showed that the BISCPM is superior to international mission for prognosis and analysis of clinical trials (IMPACT) lab model.

CONCLUSION

BISCPM is an effective model for state evaluation and prognosis prediction of TBI patients. The use of BISCPM could be of great significance for decision-making in management of TBI.

A practical method for dealing with missing Glasgow Coma Scale verbal component scores

OBJECTIVE

The Glasgow Coma Scale (GCS) is used for the assessment of impaired consciousness; however, it is not always possible to test each component, most commonly the verbal component. This affects the derivation of the GCS sum score, which has a role in systems for predicting patient outcome. Imputation of missing scores does not add extra information, but it does allow use of tools for predicting outcome that require complete data. The authors devised a simple and practical tool to employ when verbal component data are missing. They then assessed the tool's utility by application to the GCS-Pupils plus age plus CT findings (GCS-PA CT) prognostic model.

METHODS

The authors inspected data from the International Mission for Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (IMPACT) cohort to characterize the frequency of missing verbal scores. The authors identified a single verbal score to impute for each eye and motor combined sum (EM) score from distributions of verbal scores in a published database of 54,069 patients. The effectiveness of the imputed verbal score was assessed using a dataset containing information from the IMPACT and Corticosteroid Randomisation After Significant Head Injury (CRASH) databases. The authors compared the performance of the prognostic model using actual verbal scores with the performance using imputed verbal scores and assessed the information yield using Nagelkerke's R2 statistic.

RESULTS

Verbal data were most commonly missing in patients with no eye opening and with a motor score of 4 or less. The "simple" imputation model that was developed performed as well as a more complex model involving distinct combinations of eye and motor scores. The imputation model consisted of the following: EM scores 2-6, add 1; EM score 7, add 2; EM score 8 or 9, add 4; and EM score 10, add 5 to provide the GCS sum score. Modeling without information about the verbal score reduced the R2 from 32.1% to 31.4% and from 34.9% to 34.0% for predictions of death and favorable outcome at 6 months, respectively, compared with using full verbal score information.

CONCLUSIONS

This strategy is particularly valuable for imputation in clinical practice, enabling clinicians to make a rapid and reliable determination of the GCS sum score when the verbal component is not testable. This will support clinical communication and decisions based on estimates of injury severity as well as enable estimation of prognosis. The authors suggest that external validation of their imputation strategy and the performance of the GCS-PA charts should be undertaken in other clinical populations.

The Impact of Accidental Hypothermia on Mortality in Trauma Patients Overall and Patients with Traumatic Brain Injury Specifically: A Systematic Review and Meta-Analysis

Background

Accidental hypothermia is a known predictor for worse outcomes in trauma patients, but has not been comprehensively assessed in a meta-analysis so far. The aim of this systematic review and meta-analysis was to investigate the impact of accidental hypothermia on mortality in trauma patients overall and patients with traumatic brain injury (TBI) specifically.

Methods

This is a systematic review and meta-analysis using the Ovid Medline/PubMed database. Scientific articles reporting accidental hypothermia and its impact on outcomes in trauma patients were included in qualitative synthesis. Studies that compared the effect of hypothermia vs. normothermia at hospital admission on in-hospital mortality were included in two meta-analyses on (1) trauma patients overall and (2) patients with TBI specifically. Meta-analysis was performed using a Mantel–Haenszel random-effects model.

Results

Literature search revealed 264 articles. Of these, 14 studies published 1987–2018 were included in the qualitative synthesis. Seven studies qualified for meta-analysis on trauma patients overall and three studies for meta-analysis on patients with TBI specifically. Accidental hypothermia at admission was associated with significantly higher mortality both in trauma patients overall (OR 5.18 [95% CI 2.61–10.28]) and patients with TBI specifically (OR 2.38 [95% CI 1.53–3.69]).

Conclusions

In the current meta-analysis, accidental hypothermia was strongly associated with higher in-hospital mortality both in trauma patients overall and patients with TBI specifically. These findings underscore the importance of measures to avoid accidental hypothermia in the prehospital care of trauma patients.

Electronic supplementary material

The online version of this article (10.1007/s00268-020-05750-5) contains supplementary material, which is available to authorized users.

Machine learning algorithms performed no better than regression models for prognostication in traumatic brain injury

OBJECTIVE

We aimed to explore the added value of common machine learning (ML) algorithms for prediction of outcome for moderate and severe traumatic brain injury.

STUDY DESIGN AND SETTING

We performed logistic regression (LR), lasso regression, and ridge regression with key baseline predictors in the IMPACT-II database (15 studies, n = 11,022). ML algorithms included support vector machines, random forests, gradient boosting machines, and artificial neural networks and were trained using the same predictors. To assess generalizability of predictions, we performed internal, internal-external, and external validation on the recent CENTER-TBI study (patients with Glasgow Coma Scale <13, n = 1,554). Both calibration (calibration slope/intercept) and discrimination (area under the curve) was quantified.

RESULTS

In the IMPACT-II database, 3,332/11,022 (30%) died and 5,233(48%) had unfavorable outcome (Glasgow Outcome Scale less than 4). In the CENTER-TBI study, 348/1,554(29%) died and 651(54%) had unfavorable outcome. Discrimination and calibration varied widely between the studies and less so between the studied algorithms. The mean area under the curve was 0.82 for mortality and 0.77 for unfavorable outcomes in the CENTER-TBI study.

CONCLUSION

ML algorithms may not outperform traditional regression approaches in a low-dimensional setting for outcome prediction after moderate or severe traumatic brain injury. Similar to regression-based prediction models, ML algorithms should be rigorously validated to ensure applicability to new populations.

Tracheostomy practice and timing in traumatic brain-injured patients: a CENTER-TBI study

Purpose

Indications and optimal timing for tracheostomy in traumatic brain-injured (TBI) patients are uncertain. This study aims to describe the patients’ characteristics, timing, and factors related to the decision to perform a tracheostomy and differences in strategies among different countries and assess the effect of the timing of tracheostomy on patients’ outcomes.

Methods

We selected TBI patients from CENTER-TBI, a prospective observational longitudinal cohort study, with an intensive care unit stay ≥ 72 h. Tracheostomy was defined as early (≤ 7 days from admission) or late (> 7 days). We used a Cox regression model to identify critical factors that affected the timing of tracheostomy. The outcome was assessed at 6 months using the extended Glasgow Outcome Score.

Results

Of the 1358 included patients, 433 (31.8%) had a tracheostomy. Age (hazard rate, HR = 1.04, 95% CI = 1.01–1.07, p = 0.003), Glasgow coma scale ≤ 8 (HR = 1.70, 95% CI = 1.22–2.36 at 7; p < 0.001), thoracic trauma (HR = 1.24, 95% CI = 1.01–1.52, p = 0.020), hypoxemia (HR = 1.37, 95% CI = 1.05–1.79, p = 0.048), unreactive pupil (HR = 1.76, 95% CI = 1.27–2.45 at 7; p < 0.001) were predictors for tracheostomy. Considerable heterogeneity among countries was found in tracheostomy frequency (7.9–50.2%) and timing (early 0–17.6%). Patients with a late tracheostomy were more likely to have a worse neurological outcome, i.e., mortality and poor neurological sequels (OR = 1.69, 95% CI = 1.07–2.67, p = 0.018), and longer length of stay (LOS) (38.5 vs. 49.4 days, p = 0.003).

Conclusions

Tracheostomy after TBI is routinely performed in severe neurological damaged patients. Early tracheostomy is associated with a better neurological outcome and reduced LOS, but the causality of this relationship remains unproven.

Electronic supplementary material

The online version of this article (10.1007/s00134-020-05935-5) contains supplementary material, which is available to authorized users.

Baseline Predictors of Survival, Neurological Recovery, Cognitive Function, Neuropsychiatric Outcomes, and Return to Work in Patients after a Severe Traumatic Brain Injury: an Updated Review

Introduction

Severe traumatic brain injury (sTBI) is a common cause of death and disability worldwide, with long-term squeal among survivors that include cognitive deficits, psychosocial and neuropsychiatric dysfunction, failure to return to pre-injury levels of work, school and inter-personal relationships, and overall reduced quality of and satisfaction with life.

Aim

The aim of this work is to review the current literature on baseline predictors of outcomes in adults post sTBI.

Method

Most of available literature on baseline predictors of outcomes in adults post sTBI were reviewed and summarized in this work.

Results

Currently, a sizeable number of composite predictors of mortality and overall function exists; however, these instruments tend to over-estimate poor outcomes and fail to address issues like cognition, psychosocial/ neuropsychiatric dysfunction, and return to work or school.

Conclusion

This article reviews currently-identified predictors of all these outcomes.

Decompressive craniectomy for the treatment of high intracranial pressure in closed traumatic brain injury

BACKGROUND

High intracranial pressure (ICP) is the most frequent cause of death and disability after severe traumatic brain injury (TBI). It is usually treated with general maneuvers (normothermia, sedation, etc.) and a set of first-line therapeutic measures (moderate hypocapnia, mannitol, etc.). When these measures fail, second-line therapies are initiated, which include: barbiturates, hyperventilation, moderate hypothermia, or removal of a variable amount of skull bone (secondary decompressive craniectomy).

OBJECTIVES

To assess the effects of secondary decompressive craniectomy (DC) on outcomes of patients with severe TBI in whom conventional medical therapeutic measures have failed to control raised ICP.

SEARCH METHODS

The most recent search was run on 8 December 2019. We searched the Cochrane Injuries Group's Specialised Register, CENTRAL (Cochrane Library), Ovid MEDLINE(R), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid OLDMEDLINE(R), Embase Classic + Embase (OvidSP) and ISI Web of Science (SCI-EXPANDED & CPCI-S). We also searched trials registries and contacted experts.

SELECTION CRITERIA

We included randomized studies assessing patients over the age of 12 months with severe TBI who either underwent DC to control ICP refractory to conventional medical treatments or received standard care.

DATA COLLECTION AND ANALYSIS

We selected potentially relevant studies from the search results, and obtained study reports. Two review authors independently extracted data from included studies and assessed risk of bias. We used a random-effects model for meta-analysis. We rated the quality of the evidence according to the GRADE approach.

MAIN RESULTS

We included three trials (590 participants). One single-site trial included 27 children; another multicenter trial (three countries) recruited 155 adults, the third trial was conducted in 24 countries, and recruited 408 adolescents and adults. Each study compared DC combined with standard care (this could include induced barbiturate coma or cooling of the brain, or both). All trials measured outcomes up to six months after injury; one also measured outcomes at 12 and 24 months (the latter data remain unpublished). All trials were at a high risk of bias for the criterion of performance bias, as neither participants nor personnel could be blinded to these interventions. The pediatric trial was at a high risk of selection bias and stopped early; another trial was at risk of bias because of atypical inclusion criteria and a change to the primary outcome after it had started. Mortality: pooled results for three studies provided moderate quality evidence that risk of death at six months was slightly reduced with DC (RR 0.66, 95% CI 0.43 to 1.01; 3 studies, 571 participants; I² = 38%; moderate-quality evidence), and one study also showed a clear reduction in risk of death at 12 months (RR 0.59, 95% CI 0.45 to 0.76; 1 study, 373 participants; high-quality evidence). Neurological outcome: conscious of controversy around the traditional dichotomization of the Glasgow Outcome Scale (GOS) scale, we chose to present results in three ways, in order to contextualize factors relevant to clinical/patient decision-making. First, we present results of death in combination with vegetative status, versus other outcomes. Two studies reported results at six months for 544 participants. One employed a lower ICP threshold than the other studies, and showed an increase in the risk of death/vegetative state for the DC group. The other study used a more conventional ICP threshold, and results favoured the DC group (15.7% absolute risk reduction (ARR) (95% CI 6% to 25%). The number needed to treat for one beneficial outcome (NNTB) (i.e. to avoid death or vegetative status) was seven. The pooled result for DC compared with standard care showed no clear benefit for either group (RR 0.99, 95% CI 0.46 to 2.13; 2 studies, 544 participants; I² = 86%; low-quality evidence). One study reported data for this outcome at 12 months, when the risk for death or vegetative state was clearly reduced by DC compared with medical treatment (RR 0.68, 95% CI 0.54 to 0.86; 1 study, 373 participants; high-quality evidence). Second, we assessed the risk of an 'unfavorable outcome' evaluated on a non-traditional dichotomized GOS-Extended scale (GOS-E), that is, grouping the category 'upper severe disability' into the 'good outcome' grouping. Data were available for two studies (n = 571). Pooling indicated little difference between DC and standard care regarding the risk of an unfavorable outcome at six months following injury (RR 1.06, 95% CI 0.69 to 1.63; 544 participants); heterogeneity was high, with an I² value of 82%. One trial reported data at 12 months and indicated a clear benefit of DC (RR 0.81, 95% CI 0.69 to 0.95; 373 participants). Third, we assessed the risk of an 'unfavorable outcome' using the (traditional) dichotomized GOS/GOS-E cutoff into 'favorable' versus 'unfavorable' results. There was little difference between DC and standard care at six months (RR 1.00, 95% CI 0.71 to 1.40; 3 studies, 571 participants; low-quality evidence), and heterogeneity was high (I² = 78%). At 12 months one trial suggested a similar finding (RR 0.95, 95% CI 0.83 to 1.09; 1 study, 373 participants; high-quality evidence). With regard to ICP reduction, pooled results for two studies provided moderate quality evidence that DC was superior to standard care for reducing ICP within 48 hours (MD -4.66 mmHg, 95% CI -6.86 to -2.45; 2 studies, 182 participants; I² = 0%). Data from the third study were consistent with these, but could not be pooled. Data on adverse events are difficult to interpret, as mortality and complications are high, and it can be difficult to distinguish between treatment-related adverse events and the natural evolution of the condition. In general, there was low-quality evidence that surgical patients experienced a higher risk of adverse events.

AUTHORS' CONCLUSIONS

Decompressive craniectomy holds promise of reduced mortality, but the effects of long-term neurological outcome remain controversial, and involve an examination of the priorities of participants and their families. Future research should focus on identifying clinical and neuroimaging characteristics to identify those patients who would survive with an acceptable quality of life; the best timing for DC; the most appropriate surgical techniques; and whether some synergistic treatments used with DC might improve patient outcomes.

Defining New Research Questions and Protocols in the Field of Traumatic Brain Injury through Public Engagement: Preliminary Results and Review of the Literature

Traumatic brain injury (TBI) is the most common cause of death and disability in the age group below 40 years. The financial cost of loss of earnings and medical care presents a massive burden to family, society, social care, and healthcare, the cost of which is estimated at £1 billion per annum (about brain injury (online)). At present, we still lack a full understanding on the pathophysiology of TBI, and biomarkers represent the next frontier of breakthrough discoveries. Unfortunately, many tenets limit their widespread adoption. Brain tissue sampling is the mainstay of diagnosis in neuro-oncology; following on this path, we hypothesise that information gleaned from neural tissue samples obtained in TBI patients upon hospital admission may correlate with outcome data in TBI patients, enabling an early, accurate, and more comprehensive pathological classification, with the intent of guiding treatment and future research. We proposed various methods of tissue sampling at opportunistic times: two methods rely on a dedicated sample being taken; the remainder relies on tissue that would otherwise be discarded. To gauge acceptance of this, and as per the guidelines set out by the National Research Ethics Service, we conducted a survey of TBI and non-TBI patients admitted to our Trauma ward and their families. 100 responses were collected between December 2017 and July 2018, incorporating two redesigns in response to patient feedback. 75.0% of respondents said that they would consent to a brain biopsy performed at the time of insertion of an intracranial pressure (ICP) bolt. 7.0% replied negatively and 18.0% did not know. 70.0% would consent to insertion of a jugular bulb catheter to obtain paired intracranial venous samples and peripheral samples for analysis of biomarkers. Over 94.0% would consent to neural tissue from ICP probes, external ventricular drains (EVD), and lumbar drains (LD) to be salvaged, and 95.0% would consent to intraoperative samples for further analysis.

Sex Differences in Traumatic Brain Injury: What We Know and What We Should Know

There is growing recognition of the problem of male bias in neuroscience research, including in the field of traumatic brain injury (TBI) where fewer women than men are recruited to clinical trials and male rodents have predominantly been used as an experimental injury model. Despite TBI being a leading cause of mortality and disability worldwide, sex differences in pathophysiology and recovery are poorly understood, limiting clinical care and successful drug development. Given growing interest in sex as a biological variable affecting injury outcomes and treatment efficacy, there is a clear need to summarize sex differences in TBI. This scoping review presents an overview of current knowledge of sex differences in TBI and a comparison of human and animal studies. We found that overall, human studies report worse outcomes in women than men, whereas animal studies report better outcomes in females than males. However, closer examination shows that multiple factors including injury severity, sample size, and experimental injury model may differentially interact with sex to affect TBI outcomes. Additionally, we explore how sex differences in mitochondrial structure and function might contribute to possible sex differences in TBI outcomes. We propose recommendations for future investigations of sex differences in TBI, which we hope will lead to improved patient management, prognosis, and translation of therapies from bench to bedside.

The Relationship of the FOUR Score to Patient Outcome: A Systematic Review

The Full Outline of UnResponsiveness (FOUR) score assessment of consciousness replaces the Glasgow Coma Scale (GCS) verbal component with assessment of brainstem reflexes. A comprehensive overview studying the relationship between a patient's FOUR score and outcome is lacking. We aim to systematically review published literature reporting the relationship of FOUR score to outcome in adult patients with impaired consciousness. We systematically searched for records of relevant studies: CENTRAL, MEDLINE, EMBASE, Scopus, Web of Science, ClinicalTrials.gov, and OpenGrey. Prospective, observational studies of patients with impaired consciousness were included where consciousness was assessed using FOUR score, and where the outcome in mortality or validated functional outcome scores was reported. Consensus-based screening and quality appraisal were performed. Outcome prognostication was synthesized narratively. Forty records (37 studies) were identified, with overall low (n = 2), moderate (n = 25), or high (n = 13) risk of bias. There was significant heterogeneity in patient characteristics. FOUR score showed good to excellent prognostication of in-hospital mortality in most studies (area under curve [AUC], >0.80). It was good at predicting poor functional outcome (AUC, 0.80–0.90). There was some evidence that motor and eye components (also GCS components) had better prognostic ability than brainstem components. Overall, FOUR score relates closely to in-hospital mortality and poor functional outcome. More studies with standardized design are needed to better characterize it in different patient groups, confirm the differences between its four components, and compare it with the performance of GCS and its recently described derivative, the GCS-Pupils, which includes pupil response as a fourth component.

Effect of decompressive craniectomy in the postoperative expansion of traumatic intracerebral hemorrhage: a propensity score-based analysis

OBJECTIVE

Traumatic intracerebral hemorrhage (TICH) represents approximately 13%-48% of the lesions after a traumatic brain injury (TBI), and hemorrhagic progression (HP) occurs in 38%-63% of cases. In previous studies, decompressive craniectomy (DC) has been characterized as a risk factor in the HP of TICH; however, few studies have focused exclusively on this relationship. The object of the present study was to analyze the relationship between DC and the growth of TICH and to reveal any correlation with the size of the craniectomy, degree of cerebral parenchymal herniation (CPH), or volumetric expansion of the TICH.

METHODS

The authors retrospectively analyzed the records of 497 adult patients who had been consecutively admitted after suffering a severe or moderate closed TBI. An inclusion criterion was presentation with one or more TICHs on the initial or control CT. Demographic, clinical, radiological, and treatment variables were assessed for associations.

RESULTS

Two hundred three patients presenting with 401 individual TICHs met the selection criteria. TICH growth was observed in 281 cases (70.1%). Eighty-two cases (20.4%) underwent craniectomy without TICH evacuation. In the craniectomy group, HP was observed in 71 cases (86.6%); in the noncraniectomy group (319 cases), HP occurred in 210 cases (65.8%). The difference in the incidence of HP between the two groups was statistically significant (OR 3.41, p < 0.01). The mean area of the craniectomy was 104.94 ± 27.5 cm2, and the mean CPH distance through the craniectomy was 17.85 ± 11.1 mm. The mean increase in the TICH volume was greater in the groups with a craniectomy area > 115 cm2 and CPH > 25 mm (16.12 and 14.47 cm3, respectively, p = 0.01 and 0.02). After calculating the propensity score (PS), the authors followed three statistical methods-matching, stratification, and inverse probability treatment weighting (IPTW)-thereby obtaining an adequate balance of the covariates. A statistically significant relationship was found between HP and craniectomy (OR 2.77, p = 0.004). This correlation was confirmed with the three methodologies based on the PS with odds greater than 2.

CONCLUSIONS

DC is a risk factor for the growth of TICH, and there is also an association between the size of the DC and the magnitude of the volume increase in the TICH.

Predictors of Outcome After Traumatic Brain Injuries: Experience of a Tertiary Health Care Institution in Northwest India

BACKGROUND AND OBJECTIVE

Traumatic brain injury (TBI) is a major health issue in developing nations such as India along with underreporting of TBI data because of a lack of major studies targeting the population with TBI. Various lacunae from field to tertiary centers are responsible for this significant burden of TBIs. We studied the epidemiologic profile of 1150 patients with TBI including the predictors of the outcome of TBIs in a tertiary health care institution in North India to identify the modifiable factors that could be used to improve the outcome and reduce the TBI burden.

METHODS

Patients presenting with TBI to a level I trauma center were identified and enrolled in the study. Data regarding patient information from accident to discharge or death were collected as per designed format and analyzed to determine outcome predictors.

RESULTS

Mean age was 36 ± 15.8 years and 84.6% of patients were male; road traffic accident was the mode of injury in 64.26% of cases. Lack of adequate prehospital care was seen in our study. Glasgow Coma Scale score on admission, Injury Severity Score, and Rotterdam CT score were found to be the 3 statistically significant predictors of outcome in patients with TBI.

CONCLUSIONS

Knowledge about the causes, pattern, and distribution of patients with TBI from this study is helpful in policy making, research, health management, and rehabilitation at the national level in ours and in other nations.

Analysis of high-frequency PbtO2 measures in traumatic brain injury: insights into the treatment threshold

OBJECTIVE

Brain tissue hypoxia is common after traumatic brain injury (TBI). Technology now exists that can detect brain hypoxia and guide corrective therapy. Current guidelines for the management of severe TBI recommend maintaining partial pressure of brain tissue oxygen (PbtO2) > 15-20 mm Hg; however, uncertainty persists as to the optimal treatment threshold. The object of this study was to better inform the relationship between PbtO2 values and outcome for patients with TBI.

METHODS

PbtO2 measurements were prospectively and automatically collected every minute from consecutive patients admitted to the San Francisco General Hospital neurological ICU during a 6-year period. Mean PbtO2 values in TBI patients as well as the proportion of PbtO2 values below each of 75 thresholds between 0 mm Hg and 75 mm Hg over various epochs up to 30 days from the time of admission were analyzed. Patient outcomes were determined using the Glasgow Outcome Scale. The authors explored putative treatment thresholds by generating 675 separate receiver operating characteristic curves and 675 generalized linear models to examine each 1-mm Hg threshold for various epochs.

RESULTS

A total of 1,380,841 PbtO2 values were recorded in 190 TBI patients. A high proportion of PbtO2 measures were below 20 mm Hg irrespective of the examined epoch. Time below treatment thresholds was more strongly associated with outcome than mean PbtO2. A treatment window was suggested: a threshold of 19 mm Hg most robustly distinguished patients by outcome, especially from days 3-5; however, benefit was suggested from maintaining values at least as high as 33 mm Hg.

CONCLUSIONS

This analysis of high-frequency physiological data substantially informs the relationship between PbtO2 values and outcome. The results suggest a therapeutic window for PbtO2 in TBI patients along with minimum and preferred PbtO2 treatment thresholds, which may be examined in future studies. Traditional treatment thresholds that have the strongest association with outcome may not be optimal.

Outcome in Patients with Isolated Moderate to Severe Traumatic Brain Injury

Introduction

Traumatic brain injury (TBI) remains a major cause of death. Withdrawal of life-sustaining treatment (WLST) can be initiated if there is little anticipated chance of recovery to an acceptable quality of life. The aim of this study was firstly to investigate WLST rates in patients with moderate to severe isolated TBI and secondly to assess outcome data in the survivor group.

Material and Methods

A retrospective cohort study was performed. Patients aged ≥ 18 years with moderate or severe isolated TBI admitted to the ICU of a single academic hospital between 2011 and 2015 were included. Exclusion criteria were isolated spinal cord injury and referrals to and from other hospitals. Gathered data included demographics, mortality, cause of death, WLST, and Glasgow Outcome Scale (GOS) score after three months. Good functional outcome was defined as GOS > 3.

Results

Of 367 patients, 179 patients were included after applying inclusion and exclusion criteria. 55 died during admission (33%), of whom 45 (82%) after WLST. Patients undergoing WLST were older, had worse neurological performance at presentation, and had more radiological abnormalities than patients without WLST. The decision to withdraw life-sustaining treatment was made on the day of admission in 40% of patients. In 33% of these patients, this decision was made while the patient was in the Emergency Department. 71% of survivors had a good functional outcome after three months. No patient left hospital with an unresponsive wakefulness syndrome (UWS) or suffered from UWS after three months. One patient died within three months of discharge.

Conclusion

In-hospital mortality in isolated brain injured patients was 33%. The vast majority died after a decision to withdraw life-sustaining treatment. None of the patients were discharged with an unresponsive wakefulness syndrome.

Outcomes after Traumatic Brain Injury with Concomitant Severe Extracranial Injuries

Traumatic brain injury (TBI) is a leading cause of death and disability in trauma patients. Patients with TBI frequently sustain concomitant injuries in extracranial regions. The effect of severe extracranial injury (SEI) on the outcome of TBI is controversial. For 8 years, we retrospectively enrolled 485 patients with the blunt head injury with head abbreviated injury scale (AIS) ≧ 3. SEI was defined as AIS ≧ 3 injuries in the face, chest, abdomen, and pelvis/extremities. Vital signs and coagulation parameter values were also extracted from the database. Total patients were dichotomized into isolated TBI (n = 343) and TBI associated with SEI (n = 142). The differences in severity and outcome between these two groups were analyzed. To assess the relation between outcome and any variables showing significant differences in univariate analysis, we included the parameters in univariable and multivariable logistic regression analyses. Mortality was 17.8% in the isolated TBI group and 21.8% in TBI with SEI group (P = 0.38), but the Glasgow Outcome Scale (GOS) in the TBI with SEI group was unfavorable compared to the isolated TBI group (P = 0.002). Patients with SBP ≦ 90 mmHg were frequent in the TBI with SEI group. Adjusting for age, GCS, and length of hospital stay, SEI was a strong prognostic factor for mortality with adjusted ORs of 2.30. Hypotension and coagulopathy caused by SEI are considerable factors underlying the secondary insults to TBI. It is important to manage not only the brain but the whole body in the treatment of TBI patients with SEI.

Adjusting for confounding by indication in observational studies: a case study in traumatic brain injury

INTRODUCTION

Observational studies of interventions are at risk for confounding by indication. The objective of the current study was to define the circumstances for the validity of methods to adjust for confounding by indication in observational studies.

PATIENTS AND METHODS

We performed post hoc analyses of data prospectively collected from three European and North American traumatic brain injury studies including 1,725 patients. The effects of three interventions (intracranial pressure [ICP] monitoring, intracranial operation and primary referral) were estimated in a proportional odds regression model with the Glasgow Outcome Scale as ordinal outcome variable. Three analytical methods were compared: classical covariate adjustment, propensity score matching and instrumental variable (IV) analysis in which the percentage exposed to an intervention in each hospital was added as an independent variable, together with a random intercept for each hospital. In addition, a simulation study was performed in which the effect of a hypothetical beneficial intervention (OR 1.65) was simulated for scenarios with and without unmeasured confounders.

RESULTS

For all three interventions, covariate adjustment and propensity score matching resulted in negative estimates of the treatment effect (OR ranging from 0.80 to 0.92), whereas the IV approach indicated that both ICP monitoring and intracranial operation might be beneficial (OR per 10% change 1.17, 95% CI 1.01-1.42 and 1.42, 95% CI 0.95-1.97). In our simulation study, we found that covariate adjustment and propensity score matching resulted in an invalid estimate of the treatment effect in case of unmeasured confounders (OR ranging from 0.90 to 1.03). The IV approach provided an estimate in the similar direction as the simulated effect (OR per 10% change 1.04-1.05) but was statistically inefficient.

CONCLUSION

The effect estimation of interventions in observational studies strongly depends on the analytical method used. When unobserved confounding and practice variation are expected in observational multicenter studies, IV analysis should be considered.

Acute Subdural Hematoma Evacuation: Predictive Factors of Outcome

BACKGROUND

Acute subdural hematoma (aSDH) is a major cause of admission at Neurosurgical Emergency Department. Nevertheless, concerns regarding surgical indication in patients with multiple comorbidities, poor neurological status, antithrombotic therapy, and older age still persist. Therefore, a correct recognition of predictive outcome factors at hospital discharge is crucial to an appropriate neurosurgical treatment.

METHODS

Eighty-nine medical records of consecutive patients with age ≥18 years old who were submitted to aSDH evacuation between January 2008 and May 2012 were reviewed. Demographic characteristics, neurological status on admission, anticoagulant or antiplatelet therapy, and outcome on discharge were collected. Patients with insufficient data concerning these variables were excluded from the study.

RESULTS

Sixty-nine patients were included; 52% were male; 74% were older than 65 years; 41% were under oral antithrombotic therapy (OAT); at admission, 54% presented with Glasgow coma scale (GCS) ≤8; 23% were submitted to a craniectomy instead of a craniotomy; 26% of the patients died, 32% were dependent, and 42% were independent on discharge. Crude analysis revealed craniectomy, A/A pupils, GCS ≤8 at admission statistically significant related with the worst outcome (P < 0.05). In the adjusted evaluation only A/A pupils (P = 0.04) was associated to poor outcome (spontaneous etiology P = 0.052). Considering daily living independency at hospital discharge, either male gender (P = 0.044) and A/A pupils (P = 0.030) were related to the worst outcome. No effect of age in outcome was observed.

CONCLUSIONS

Male gender and A/A pupils are associated with lower probability of achieving independency living at hospital discharge. A/A pupils, low GCS at admission, spontaneous etiology, and craniectomy were associated with the worst outcome. Age and OAT were not predictive factors in this series. Caution should be taken when considering these factors in the surgical decision.

A pilot study of hyperoxemia on neurological injury, inflammation and oxidative stress

BACKGROUND

Normobaric hyperoxia is used to alleviate secondary brain ischaemia in patients with traumatic brain injury (TBI), but clinical evidence is limited and hyperoxia may cause adverse events.

METHODS

An open label, randomised controlled pilot study comparing blood concentrations of reactive oxygen species (ROS), interleukin 6 (IL-6) and neuron-specific enolase (NSE) between two different fractions of inspired oxygen in severe TBI patients on mechanical ventilation.

RESULTS

We enrolled 27 patients in the Fi O₂ 0.40 group and 38 in the Fi O₂ 0.70 group; 19 and 23 patients, respectively, completed biochemical analyses. In baseline, there were no differences between Fi O₂ 0.40 and Fi O₂ 0.70 groups, respectively, in ROS (64.8 nM [22.6-102.1] vs. 64.9 nM [26.8-96.3], P = 0.80), IL-6 (group 92.4 pg/ml [52.9-171.6] vs. 94.3 pg/ml [54.8-133.1], P = 0.52) or NSE (21.04 ug/l [14.0-30.7] vs. 17.8 ug/l [14.1-23.9], P = 0.35). ROS levels did not differ at Day 1 (24.2 nM [20.6-33.5] vs. 29.2 nM [22.7-69.2], P = 0.10) or at Day 2 (25.4 nM [21.7-37.4] vs. 47.3 nM [34.4-126.1], P = 0.95). IL-6 concentrations did not differ at Day 1 (112.7 pg/ml [65.9-168.9) vs. 83.9 pg/ml [51.8-144.3], P = 0.41) or at Day 3 (55.0 pg/ml [34.2-115.6] vs. 49.3 pg/ml [34.4-126.1], P = 0.95). NSE levels did not differ at Day 1 (15.9 ug/l [9.0-24.3] vs. 15.3 ug/l [12.2-26.3], P = 0.62). There were no differences between groups in the incidence of pulmonary complications.

CONCLUSION

Higher fraction of inspired oxygen did not increase blood concentrations of markers of oxidative stress, inflammation or neurological injury or the incidence of pulmonary complications in severe TBI patients on mechanical ventilation.

Central Infusion of Insulin-Like Growth Factor-1 Increases Hippocampal Neurogenesis and Improves Neurobehavioral Function after Traumatic Brain Injury

Traumatic brain injury (TBI) produces neuronal dysfunction and cellular loss that can culminate in lasting impairments in cognitive and motor abilities. Therapeutic agents that promote repair and replenish neurons post-TBI hold promise in improving recovery of function. Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor capable of mediating neuroprotective and neuroplasticity mechanisms. Targeted overexpression of IGF-1 enhances the generation of hippocampal newborn neurons in brain-injured mice; however, the translational neurogenic potential of exogenously administered IGF-1 post-TBI remains unknown. In a mouse model of controlled cortical impact, continuous intracerebroventricular infusion of recombinant human IGF-1 (hIGF) for 7 days, beginning 15 min post-injury, resulted in a dose-dependent increase in the number of immature neurons in the hippocampus. Infusion of 10 μg/day of IGF-1 produced detectable levels of hIGF-1 in the cortex and hippocampus and a concomitant increase in protein kinase B activation in the hippocampus. Both motor function and cognition were improved over 7 days post-injury in IGF-1-treated cohorts. Vehicle-treated brain-injured mice showed reduced hippocampal immature neuron density relative to sham controls at 7 days post-injury. In contrast, the density of hippocampal immature neurons in brain-injured mice receiving acute onset IGF-1 infusion was significantly higher than in injured mice receiving vehicle and equivalent to that in sham-injured control mice. Importantly, the neurogenic effect of IGF-1 was maintained with as much as a 6-h delay in the initiation of infusion. These data suggest that central infusion of IGF-1 enhances the generation of immature neurons in the hippocampus, with a therapeutic window of at least 6 h post-injury, and promotes neurobehavioral recovery post-TBI.

Simplifying the use of prognostic information in traumatic brain injury. Part 1: The GCS-Pupils score: an extended index of clinical severity

OBJECTIVE

Glasgow Coma Scale (GCS) scores and pupil responses are key indicators of the severity of traumatic brain damage. The aim of this study was to determine what information would be gained by combining these indicators into a single index and to explore the merits of different ways of achieving this.

METHODS

Information about early GCS scores, pupil responses, late outcomes on the Glasgow Outcome Scale, and mortality were obtained at the individual patient level by reviewing data from the CRASH (Corticosteroid Randomisation After Significant Head Injury; n = 9,045) study and the IMPACT (International Mission for Prognosis and Clinical Trials in TBI; n = 6855) database. These data were combined into a pooled data set for the main analysis.

Methods of combining the Glasgow Coma Scale and pupil response data varied in complexity from using a simple arithmetic score (GCS score [range 3–15] minus the number of nonreacting pupils [0, 1, or 2]), which we call the GCS-Pupils score (GCS-P; range 1–15), to treating each factor as a separate categorical variable. The content of information about patient outcome in each of these models was evaluated using Nagelkerke’s R2.

RESULTS

Separately, the GCS score and pupil response were each related to outcome. Adding information about the pupil response to the GCS score increased the information yield. The performance of the simple GCS-P was similar to the performance of more complex methods of evaluating traumatic brain damage. The relationship between decreases in the GCS-P and deteriorating outcome was seen across the complete range of possible scores. The additional 2 lowest points offered by the GCS-Pupils scale (GCS-P 1 and 2) extended the information about injury severity from a mortality rate of 51% and an unfavorable outcome rate of 70% at GCS score 3 to a mortality rate of 74% and an unfavorable outcome rate of 90% at GCS-P 1. The paradoxical finding that GCS score 4 was associated with a worse outcome than GCS score 3 was not seen when using the GCS-P.

CONCLUSIONS

A simple arithmetic combination of the GCS score and pupillary response, the GCS-P, extends the information provided about patient outcome to an extent comparable to that obtained using more complex methods. The greater range of injury severities that are identified and the smoothness of the stepwise pattern of outcomes across the range of scores may be useful in evaluating individual patients and identifying patient subgroups. The GCS-P may be a useful platform onto which information about other key prognostic features can be added in a simple format likely to be useful in clinical practice.