Assessment of GCS and FOUR Score as Prognostic Indicators for Hospital Stay and Morbidity in Traumatic Brain Injury Patients: An Observational Study

ABSTRACT

Aim:

The objective of the present research was to evaluate variations in hospital stay as well as morbidity based on the Glasgow Coma Scale (GCS) and Full Outline of Un-Responsive (FOUR) scores for patients who had traumatic brain injury (TBI).

Materials and Methods:

A total of 107 patients with TBI patients who attended the emergency department of MES Medical College, Perinthalmanna, were enrolled into the study. FOUR and GCS scoring systems were used to assess the patients within 24 hours of the presentation to the emergency department. Both FOUR and GCS scoring systems were assessed at the same time. The outcome was measured in terms of length of hospital stay and morbidity, which was assessed using modified Rankin score. Chi-square test was used to calculate sensitivity, specificity, positive predictive value, and negative predictive value. The area under the curve (AUC) was calculated using receiver operating characteristic curve analysis. A P value <0.05 was considered significant.

Results:

We found a strong positive correlation between GCS and FOUR score with a Spearman coefficient of 0.9. Comparison of AUC between GCS score and FOUR score showed a statistically significant difference (P = 0.0044), predicting that FOUR score was a better predictor of hospital stay (>15 days) than GCS score. Comparison of AUC between GCS score and FOUR score showed a significant statistical difference (P = 0.0002), showing that FOUR score was a better predictor of morbidity than GCS.

Conclusion:

FOUR score was a better predictor of hospital stay and morbidity as compared to GCS score.

INTRODUCTION

Traumatic brain injury (TBI) is an injury that can change the way the brain normally works and is caused by an external force to the head. The severity of TBI may range from “mild” (i.e., a brief change in mental status or consciousness) to “severe” (i.e., an extended period of unconsciousness or amnesia after an injury). Mild TBI accounts for nearly 75% of all TBIs. Health care professionals may describe a concussion as a “mild” brain injury because most concussion symptoms typically resolve in days to weeks, but all TBIs—mild, moderate, or severe—are serious injuries and have the potential for long-term consequences. The total cost of emergency department visits and hospitalizations, either alone or in combination with other injuries, exceeds $82 billion annually—this includes medical and work loss costs.[1] Among all age groups, motor vehicle crashes and traffic-related incidents are the third leading cause of TBI (14%). Assaults are the cause of 10% of TBIs in the general population; they account for 3% of all TBIs among children aged 0–14 years and 1% among adults aged 65 years and older. Assaults include injuries inflicted by another person with an intent to injure or kill, such as fights, child maltreatment (e.g., shaken baby or abusive head trauma), and intimate partner violence or elder abuse. Falls are the leading cause of TBI (40%) in countries like United States. They cause more than half (55%) of all TBIs among children aged 0–14 years and 81% of all TBIs among adults aged 65 years and older.[2] The type, direction, intensity, and duration of forces all contribute to the characteristics and severity of TBI. Forces that may contribute to TBI include angular, rotational, shear, and translational forces. Even in the absence of an impact, significant acceleration or deceleration of the head can cause TBI; however, in most cases, a combination of impact and acceleration is probably to blame. Forces involving the head striking or being struck by something, termed contact or impact loading, are the cause of most focal injuries, and movement of the brain within the skull, termed non-contact or inertial loading, usually causes diffuse injuries.[3] One type of focal injury, cerebral laceration, occurs when the tissue is cut or torn. Such tearing is common in the orbito-frontal cortex in particular because of bony protrusions on the interior skull ridge above the eyes. In a similar injury, cerebral contusion (bruising of the brain tissue), blood is mixed among tissues. In contrast, intracranial hemorrhage involves bleeding that is not mixed with tissues. With mild TBI, the patient may remain conscious or may lose consciousness for a few seconds or minutes. Other symptoms of mild TBI include headache, vomiting, nausea, lack of motor coordination, dizziness, difficulty balancing, light headedness, blurred vision or tired eyes, ringing in the ears, bad taste in the mouth, fatigue or lethargy, and changes in sleep patterns. A person with a moderate or severe TBI may have a headache that does not go away, repeated vomiting or nausea, convulsions, an inability to awaken, dilation of one or both pupils, slurred speech, aphasia (word-finding difficulties), dysarthria (muscle weakness that causes disordered speech), weakness or numbness in the limbs, loss of coordination, confusion, restlessness, or agitation. Cognitive and social deficits have long-term consequences for the daily lives of people with moderate to severe TBI but can be improved with appropriate rehabilitation.[4] The Glasgow Coma Scale (GCS), the most commonly used system for classifying TBI severity, grades a person’s level of consciousness on a scale of 3–15 based on verbal, motor, and eye-opening reactions to stimuli. It is generally agreed that a TBI with a GCS of 13 or above is mild, 9–12 is moderate, and 8 or below is severe. However, the GCS presents some weaknesses, such as limited utility in intubated patients as well as an inability to assess brainstem reflexes. Considering such limitations, a new coma score, the Full Outline of Un-Responsiveness (FOUR) score, has been developed to overcome these shortcomings. The FOUR score also provides further neurological details that might lead to a better prediction of outcomes in coma patients. The FOUR score has four components: eye responses, motor responses, brainstem reflexes, and respiration patterns. Each component ranges from a minimal value of 0 to a maximal value of 4. The total FOUR score ranges from a minimum of 0 to a maximum of 16.[5]

AIM OF THE PRESENT STUDY

The objective of the present research was to evaluate variations in hospital stay as well as morbidity based on the GCS and FOUR scores for patients who had TBI.

MATERIALS AND METHODS

A total of 107 patients were included in the study, who were recruited from the emergency department of MES Medical College, Perinthalmanna. The ethical clearance and the consents were obtained. Adult patients (>18 years) presenting to the emergency department with TBI were included in the study. Previous neurological problems or insufficient medical records disqualified the patients. Demographic data, injury characteristics, and clinical variables like mechanism of injury, time from injury to hospital admission, and concomitant injuries upon admission were considered. Each patient’s GCS score—eye-opening, verbal response, and motor response—was examined. The FOUR score assessed ocular responses, brainstem reflexes, and breathing rhythm. Patients were monitored for 15 days. The outcome was measured in terms of length of hospital stay and morbidity, which was assessed using modified Rankin scale. Disability was categorized as mild/no disability and moderate/severe disability with mRS ≤3 and >3. The area under the curve (AUC) was used to calculate predictors of morbidity and hospital stay. Logistic regression analysis was used to examine GCS and FOUR scores independently while controlling for covariates. Correlation between GCS and FOUR score was calculated using the Spearman correlation coefficient. A P value <0.05 was considered significant. Statistical analysis was performed using MedCalc trial version.

RESULTS

The study analysis showed that a majority of the patients (65.42%) were in the 25–65 age-group category. Approximately 10% patients were below age 25 years, and 25% patients were aged above 65 years. Gender analysis showed that males outnumbered females in the study. It was observed that road traffic accidents (RTAs) were the cause of TBI in 90% patients. Out of 107 patients, 27 patients required hospital admission for more than 15 days. Among the 27 patients, 11.11% patients each had GCS ≤5 and FOUR score ≤4. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FOUR score for hospital stay (>15 days) were 11.11%, 100%, 100, and 71.08, respectively (P < 0.0001). The area under the curve (AUC) for GCS and FOUR score was 0.611 and 0.719, respectively. Comparison of AUC between GCS score and FOUR score showed a statistical significant difference (P = 0.0044), predicting that FOUR score was a better predictor of hospital stay (>15 days) than GCS score [Table 1 and Figure 1]. As far as morbidity assessment was concerned, our analysis found that three patients each with morbidities had GCS ≤5 and FOUR ≤4. Morbidities were grouped into those with mRS ≥3 and <3. The sensitivity, specificity, PPV, and NPV of GCS for morbidity were 12.5%, 95.16%, 50, and 73.75, respectively (P < 0.0001). The sensitivity, specificity, PPV, and NPV of FOUR score for morbidity were 12.5%, 100%, 100, and 74.7, respectively (P < 0.0001). Comparison of AUC between GCS score and FOUR score showed a significant statistical difference (P = 0.0002), showing that FOUR score was a better predictor of morbidity than GCS [Table 2 and Figure 2].

Table 1.

Diagnostic values of GCS and FOUR score for prediction of hospital stay

	GCS score	FOUR score
Sensitivity	11.11%	11.11%
Specificity	94.92%	100%
Positive Predictive Value	50	100
Negative Predictive value	70	71.08
Confidence Interval	0.693 to 0.874	0.848 to 0.971
AUC	0.794	0.925
P	<0.001	<0.001

Figure 1.

ROC curve for prediction of hospital stay

Table 2.

Diagnostic values of GCS and FOUR score for prediction of morbidity

	GCS score	FOUR score
Sensitivity	12.50%	12.5%
Specificity	95.16	100%
Positive Predictive Value	50.0	100
Negative Predictive value	73.75	74.7
Confidence Interval	0.787 to 0.924	0.891 to 0.983
AUC	0.866	0.951
P	<0.0001	<0.0001

Figure 2.

ROC curve for morbidity

DISCUSSION

GCS is the most commonly used scale to assess the status of comatose patients.[6] It is not as useful as a single acute measure of severity as it is a tool to measure disease progression over time. The GCS may additionally be affected by drugs, alcohol, medications, paralytics, or ocular injuries. Finally, the scale lacks the granularity necessary to assess minor TBI. The rationale for the development of the FOUR score was to create a clinical grading scale for the assessment of patients with an impaired level of consciousness that can be used in patients with or without endotracheal intubation. Many survivors of head injury suffer long-lasting disability, which includes physical as well as mental deficits, making interpretation difficult. There are various scores to assess the morbidity, such as Glasgow Outcome Scale (GOS) and Modified Rankin Scale (mRS), which are widely used, but they lack intelligent quotient assessment and language function assessment. To overcome it, other scores like Rancho Los Amigos level of cognitive function scale, Rappaport’s disability rating scale, Hoensbroeck disability scale for brain injury, and functional status examination are used.[7] Khanal et al. compared the FOUR score with GCS for prognostication of neurosurgical patients using GOS. They divided the patients into two groups: group I patients with GCS and FOUR score <8 and group II with GCS and FOUR >8. GOS, ICU stay, and ventilator days showed a better correlation with the group I FOUR score as compared to GCS. The motor component of both the scores had significant relation with outcome variables. FOUR score’s motor sub-component had statistically significant relation with ICU stay and duration of ventilator support. The FOUR score is comparable to the GCS in predicting outcome after head trauma and has better correlation with outcome parameters such as GOS, ventilator days, and ICU stay.[8] Grote et al. investigated the diagnostic value of GCS to identify severe TBI in multiple-injured patients. Nine percent of all cases (n = 1643) had a GCS ≤8 without severe TBI. The diagnostic value of GCS ≤8 for severe TBI in patients with multiple injuries had a low sensitivity (56.1%) but a higher specificity (82.2%). The study indicated that the GCS (as defined ≤8) in unconsciousness patients with multiple injuries showed only a moderate correlation with the diagnosis of severe TBI.[9] We also found that FOUR score is a better predictor of length of hospital stay and morbidity than GCS. In our study, considering several constraints, the single-center studies may limit generalizability. To better understand GCS and FOUR score prediction abilities, future studies could include longitudinal evaluations and broader outcome measurements.[10]

CONCLUSION

The FOUR score is an accurate predictor of outcome in TBI patients. It is easy to learn, remember, and administer. It has some advantages over GCS; for example, all its components can be rated in intubated patients, it gives all components equal weight, and it allows the examiner to localize lesions and diagnose a locked-in state. We also found that FOUR score is a better predictor of length of hospital stay and morbidity than GCS in TBI patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.