Impact of traumatic brain injury on risk for schizophrenia and bipolar disorder

The impact of traumatic brain injury (TBI) on subsequent risk of schizophrenia (SCZ) or bipolar disorder (BD) remains contested. Possible genetic and environmental confounding effects have also been understudied. Therefore, we aim to investigate the impact of TBI on the risk of SCZ and BD and whether the effect varies by injury severity, age at injury, and sex. We identified 4,184 SCZ and 18,681 BD cases born between 1973 and 1998 in the Swedish National Registers. Case-control samples matched (1:5) on birth year, sex, and birthplace were created along with a family design study, with cases matched to non-case full siblings. TBI was associated with higher risk of SCZ and BD (IRR=1.33 for SCZ, IRR=1.78 for BD). The association remained significant in the sibling comparison study. Moderate or severe TBI was associated with higher risk for both SCZ and BD compared to mild TBI. Older age at injury was associated with higher risk of SCZ and BD, and the effect of TBI was stronger in women than men. Findings indicate that TBI is a risk factor for both SCZ and BD with differential impact by age, severity and sex and that this association cannot be explained by familial confounding alone.

Traumatic Brain Injury in Patients With Frontal Sinus Fractures

Traumatic brain injury (TBI) is an insult to the brain from an external mechanical force that may lead to short or long-term impairment. Traumatic brain injury has been reported in up to 83% of craniofacial fractures involving the frontal sinus. However, the risk factors for TBI at presentation and persistent neurological sequelae in patients with frontal sinus fractures remain largely unstudied. The authors aim to evaluate the prevalence and risk factors associated with TBI on presentation and neurological sequelae in these patients. The authors retrospectively reviewed patients who presented with traumatic frontal sinus fractures in 2019. The authors' primary outcome was the prevalence of concomitant TBI on presentation, which authors defined as any patient with neurological symptoms/signs on presentation and/or patients with a Glasgow Coma Scale <15 with no acute drug or alcohol intoxication or history of dementia or other neurocognitive disorder. The authors' secondary outcome was the incidence of neurological sequelae after 1 month of injury. Bivariate analysis and multivariate logistic regression were performed. A total of 56 patients with frontal sinus fractures were included. Their median (interquartile range) age was 47 (31-59) years, and the median (interquartile range) follow-up was 7.3 (1.3-76.5) weeks. The majority were males [n = 48 (85.7%)] and non-Hispanic whites [n = 35 (62.5%)]. Fall was the most common mechanism of injury [n = 15 (26.8%)]. Of the 56 patients, 46 (82.1%) had concomitant TBI on presentation. All patients who had combined anterior and posterior table frontal sinus fractures [n = 37 (66.1%)] had TBI on presentation. These patients had 13 times the odds of concomitant TBI on presentation [adjusted odds ratio (95% CI): 12.7 (2.3-69.0)] as compared with patients with isolated anterior or posterior table fractures. Of 34 patients who were followed up more than 1 month after injury, 24 patients (70.6%) had persistent neurological sequelae, most commonly headache [n = 16 (28.6%)]. Patients who had concomitant orbital roof fractures had 32 times the odds of neurological sequelae after 1 month of injury [adjusted odds ratio (95% CI): 32 (2.4->100)]. Emergency physicians and referring providers should maintain a high degree of suspicion of TBI in patients with frontal sinus fractures. Head computed tomography at presentation and close neurological follow-up are recommended for patients with frontal sinus fracture with combined anterior and posterior table fractures, as well as those with concomitant orbital roof fractures.

Case identification of non-traumatic brain injury in youth using linked population data

BACKGROUND

Population-level administrative data provides a cost-effective means of monitoring health outcomes and service needs of clinical populations. This study aimed to present a method for case identification of non-traumatic brain injury in population-level data and to examine the association with sociodemographic factors.

METHODS

An estimated resident population of youth aged 0-24 years was constructed using population-level datasets within the New Zealand Integrated Data Infrastructure. A clinical consensus committee reviewed the International Classification of Diseases Ninth and Tenth Editions codes and Read codes for inclusion in a case definition. Cases were those with at least one non-traumatic brain injury code present in the five years up until 30 June 2018 in one of four databases in the Integrated Data Infrastructure. Rates of non-traumatic brain injury were examined, both including and excluding birth injury codes and across age, sex, ethnicity, and socioeconomic deprivation groups.

RESULTS

Of the 1 579 089 youth aged 0-24 years on 30 June 2018, 8154 (0.52%) were identified as having one of the brain injury codes in the five-years to 30 June 2018. Rates of non-traumatic brain injury were higher in males, children aged 0-4 years, Māori and Pacific young people, and youth living with high levels of social deprivation.

CONCLUSION

This study presents a comprehensive method for case identification of non-traumatic brain injury using national population-level administrative data.

Identification of clinically relevant patient endotypes in traumatic brain injury using latent class analysis

Traumatic brain injury (TBI) is a complex condition where heterogeneity impedes the advancement of care. Understanding the diverse presentations of TBI is crucial for personalized medicine. Our study aimed to identify clinically relevant patient endotypes in TBI using latent class analysis based on comorbidity data. We used the Medical Information Mart for Intensive Care III database, which includes 2,629 adult TBI patients. We identified five stable endotypes characterized by specific comorbidity profiles: Heart Failure and Arrhythmia, Healthy, Renal Failure with Hypertension, Alcohol Abuse, and Hypertension. Each endotype had distinct clinical characteristics and outcomes: The Heart Failure and Arrhythmia endotype had lower survival rates than the Renal Failure with Hypertension despite featuring fewer comorbidities overall. Patients in the Hypertension endotype had higher rates of neurosurgical intervention but shorter stays in contrast to the Alcohol Abuse endotype which had lower rates of neurosurgical intervention but significantly longer hospital stays. Both endotypes had high overall survival rates comparable to the Healthy endotype. Logistic regression models showed that endotypes improved the predictability of survival compared to individual comorbidities alone. This study validates clinical endotypes as an approach to addressing heterogeneity in TBI and demonstrates the potential of this methodology in other complex conditions.

Access to Rehabilitation After Hospitalization for Traumatic Brain Injury: A National Longitudinal Cohort Study in Sweden

BACKGROUND

Rehabilitation is suggested to improve outcomes following traumatic brain injury (TBI), however, the extent of access to rehabilitation among TBI patients remains unclear.

OBJECTIVE

To examine the level of access to rehabilitation after TBI, and its association with health and sociodemographic factors.

METHOD

We conducted a longitudinal cohort study using Swedish nationwide healthcare and sociodemographic registers. We identified 15 880 TBI patients ≥18 years hospitalized ≥3 days from 2008 to 2012 who were stratified into 3 severity groups; grade I (n = 1366; most severe), grade II (n = 5228), and grade III (n = 9268; least severe). We examined registered contacts with specialized rehabilitation or geriatric care (for patients ≥65 years) during the hospital stay, and/or within 1 year post-discharge. We performed a generalized linear model analysis to estimate the risk ratio (RR) for receiving specialized rehabilitation or geriatric care after a TBI based on sociodemographic and health factors.

RESULTS

Among TBI patients, 46/35% (grade I), 14/40% (grade II), and 5/18% (grade III) received specialized rehabilitation or geriatric care, respectively. Being currently employed or studying was positively associated (RR 1.7, 2.3), while living outside of a city area was negatively associated (RR 0.36, 0.79) with receiving specialized rehabilitation or geriatric care. Older age and a prior substance use disorder were negatively associated with receiving specialized rehabilitation (RR 0.51 and 0.81).

CONCLUSION

Our results suggest insufficient and unequal access to rehabilitation for TBI patients, highlighting the importance of organizing and standardizing post-TBI rehabilitation to meet the needs of patients, regardless of their age, socioeconomic status, or living area.

Area-Level Socioeconomic Inequalities in Intracranial Injury-Related Hospitalization in Korea: A Retrospective Analysis of Data From Korea National Hospital Discharge Survey 2008-2015

BACKGROUND

Although inequality in traumatic brain injury (TBI) by individual socioeconomic status (SES) exists, interventions to modify individual SES are difficult. However, as interventions for area-based SES can affect the individual SES, monitoring or public health intervention can be planned. We analyzed the effect of area-based SES on hospitalization for TBI and revealed yearly inequality trends to provide a basis for health intervention.

METHODS

We included patients who were hospitalized due to intracranial injuries (ICIs) between 2008 and 2015 as a measure of severe TBI with data provided by the Korea National Hospital Discharge Survey. Area-based SES was synthesized using the 2010 census data. We assessed inequalities in ICI-related hospitalization rates using the relative index of inequality and the slope index of inequality for the periods 2008-2009, 2010-2011, 2012-2013, and 2014-2015. We analyzed the trends of these indices for the observation period by age and sex.

RESULTS

The overall relative indices of inequality for each 2-year period were 1.82 (95% confidence interval, 1.5-2.3), 1.97 (1.6-2.5), 2.01 (1.6-2.5), and 2.01 (1.6-2.5), respectively. The overall slope indices of inequality in each period were 38.74 (23.5-54.0), 36.75 (21.7-51.8), 35.65 (20.7-50.6), and 43.11 (27.6-58.6), respectively. The relative indices of inequality showed a linear trend for men (P = 0.006), which was most evident in the ≥ 65-year age group.

CONCLUSION

Inequality in hospitalization for ICIs by area-based SES tended to increase during the observation period. Practical preventive interventions and input in healthcare resources for populations with low area-based SES are likely needed.

Association of Traumatic Brain Injury Severity and Self-Reported Neuropsychiatric Symptoms in Wounded Military Service Members

The impact of traumatic brain injury (TBI) severity and loss of consciousness (LOC) on the development of neuropsychiatric symptoms was studied in injured service members (SMs; n = 1278) evacuated from combat settings between 2003 and 2012. TBI diagnoses of mild TBI (mTBI) or moderate-to-severe TBI (MS-TBI) along with LOC status were identified using International Classification of Diseases, Ninth Revision (ICD-9) codes and the Defense and Veterans Brain Injury Center Standard Surveillance Case Definition for TBI. Self-reported psychiatric symptoms were evaluated for post-traumatic stress disorder (PTSD) with the PTSD Checklist, Civilian Version for PTSD, the Patient Health Questionnaire-9 for major depressive disorder (MDD), and the Patient Health Questionnaire-15 for somatic symptom disorder (SSD) in two time periods post-injury: Assessment Period 1 (AP1, 0.0-2.5 months) and Assessment Period 2 (AP2, 3-12 months). mTBI, but not MS-TBI, was associated with increased neuropsychiatric symptoms: PTSD in AP1 and AP2; MDD in AP1; and SSD in AP2. A subgroup analysis of mTBI with and without LOC revealed that mTBI with LOC, but not mTBI without LOC, was associated with increased symptoms as compared to non-TBI: PTSD in AP1 and AP2; MDD in AP1; and SSD in AP1 and AP2. Moreover, mTBI with LOC was associated with increased MDD symptoms in AP2, and SSD symptoms in AP1 and AP2, compared to mTBI without LOC. These findings reinforce the need for the accurate characterization of TBI severity and a multi-disciplinary approach to address the devastating impacts of TBI in injured SMs.

Traumatic Brain Injury and Risk of Long-Term Nursing Home Entry among Older Adults: An Analysis of Medicare Administrative Claims Data

Traumatic brain injury (TBI) is a leading cause of injury-related disability among older adults, and there is increasing interest in post-discharge management as this population grows. We evaluated the association between TBI and long-term nursing home (NH) entry among a nationally representative sample of older adults. We identified 207,355 adults aged ≥65 years who received a diagnosis of either a TBI, non-TBI trauma, or were uninjured between January 2008 and June 2015 from a 5% sample of Medicare beneficiaries. The NH entry was operationalized as the first NH admission that resulted in a stay ≥100 days. Time to NH entry was calculated as the difference between the NH entry date and the index date (the date of TBI, non-TBI trauma, or inpatient/outpatient visit in the uninjured group). We used cause-specific Cox proportional hazards models with stabilized inverse probability of exposure weights to model time to NH entry as a function of injury in the presence of death as a competing risk and generated hazard ratios (HR) and 95% confidence intervals (CI). After excluding beneficiaries living in a NH at index, there were 60,600 TBI, 63,762 non-TBI trauma, and 69,893 uninjured beneficiaries in the sample. In weighted models, beneficiaries with TBI entered NHs at higher rates relative to the non-TBI trauma (HR 1.15; 95% CI 1.10, 1.20) and uninjured (HR 1.67; 95% CI 1.60, 1.74) groups. Future research should focus on interventions to retain older adult TBI survivors within the community.

Traumatic Brain Injury in Honduras: The Use of a Paper-based Surveillance System to Characterize Injuries Patterns

BACKGROUND

Traumatic brain injuries (TBI) are a leading cause of death and disability worldwide. Violence is the leading cause of mortality in Honduras. However, the incidence and impact of TBI in this low-middle income country (LMIC) is unknown. The aim of this study is to describe the epidemiology of TBI in Honduras, as captured by an injury surveillance tool in the country's major referral center.

METHODS

A cross sectional review of all TBI-related emergency department visits at the main referral hospital in Honduras from January to December 2013 was conducted. The calculation of descriptive statistics from Injury Surveillance System (InSS) data was performed.

RESULTS

Of 17,971 total injuries seen in 2013, 20% were traumatic brain injuries (n=3,588). The main mechanisms of injury were falls (41.11%), road traffic accidents (23.91%), blunt trauma (20.82%), penetrating knife injuries (5.85%), and firearm injuries (2.26%). Most TBI were classified as mild; 99.69% (Glasgow Coma Scale=15). Emergency room mortality was low (1.11%). The modified Kampala Trauma Score median was 8 (interquartile range 7-8).

CONCLUSION

Mild TBI accounts for a significant percentage of all injuries presenting to a high-volume referral center in Honduras in 2013. Despite the high incidence of violence in this country, most TBI were accidental, secondary to road traffic accidents and falls. Further research is required with more recent data as well as with prospective data collection methods.

Traumatic brain injury hospitalizations in Belgium: A brief overview of incidence, population characteristics, and outcomes

Background

There is a need for complete and accurate epidemiological studies for traumatic brain injury (TBI). Secondary use of administrative data can provide country-specific population data across the full spectrum of disease.

Aim

This study aims to provide a population-based overview of Belgian TBI hospital admissions as well as their health-related and employment outcomes.

Methods

A combined administrative dataset with deterministic linkage at individual level was used to assess all TBI hospitalizations in Belgium during the year 2016. Discharge data were used for patient selection and description of injuries. Claims data represented the health services used by the patient and health-related follow-up beyond hospitalization. Finally, social security data gave insight in changes to employment situation.

Results

A total of 17,086 patients with TBI were identified, with falls as the predominant cause of injury. Diffuse intracranial injury was the most common type of TBI and 53% had injuries to other body regions as well. In-hospital mortality was 6%. The median length of hospital stay was 2 days, with 20% being admitted to intensive care and 28% undergoing surgery. After hospitalization, 23% had inpatient rehabilitation. Among adults in the labor force pre-injury, 72% of patients with mild TBI and 59% with moderate-to-severe TBI returned to work within 1 year post-injury.

Discussion

Administrative data are a valuable resource for population research. Some limitations need to be considered, however, which can in part be overcome by enrichment of administrative datasets with other data sources such as from trauma registries.

Mortality and Risk Factors in Isolated Traumatic Brain Injury Patients: A Prospective Cohort Study

INTRODUCTION

Outcomes in patients with isolated traumatic brain injury (iTBI) have not been evaluated comprehensively in low-income and middle-income countries. We aimed to study the in-hospital iTBI mortality and its associated risk factors in a prospective multicenter Indian trauma registry.

METHODS

Patients with iTBI (head and neck Abbreviated Injury Score ≥2 and other region Abbreviated Injury Score ≤2) were included. Study variables comprised age, gender, mechanism of injury, systolic blood pressure (SBP) at arrival, Glasgow Coma Scale (GCS) score - classified as mild (13-15), moderate (9-12), and severe (3-8), transfer status, and time to presentation at any participating hospital. A multivariable logistic regression was performed to assess the impact of these factors on 24-h and 30-d mortality following iTBI.

RESULTS

Among 5042 included patients, 24-h and 30-d in-hospital mortalities were 5.9% and 22.4%. On a regression analysis, 30-d mortality was associated with age ≥45 y (odds ratio [OR] = 2.1 [1.6-2.7]), railway injury mechanisms (OR = 2.1 [1.3-3.5]), SBP <90 mmHg (OR = 2.6 [1.6-4.1]), and moderate (OR = 3.8 [3.0-5.0]) to severe (OR = 21.1 [16.8-26.7]) iTBI based on GCS scores. 24-h mortality showed similar trends. Patients transferred to the participating hospitals from other centers had higher odds of 30-d mortality (OR = 1.4 [1.2-1.8]) compared to those arriving directly. Those who received neurosurgical intervention had lower odds of 24-h mortality (0.3 [0.2-0.4]).

CONCLUSIONS

Age ≥45 y, GCS score ≤12, and SBP <90 mmHg at arrival increased the risk of in-hospital mortality from iTBI.

Repetitive Traumatic Brain Injury Among Older Adults

OBJECTIVE

To determine the incidence of and assess risk factors for repetitive traumatic brain injury (TBI) among older adults in the United States.

DESIGN

Retrospective cohort study.

SETTING

Administrative claims data obtained from the Centers for Medicare & Medicaid Services' Chronic Conditions Data Warehouse.

PARTICIPANTS

Individuals 65 years or older and diagnosed with TBI between July 2008 and September 2012 drawn from a 5% random sample of US Medicare beneficiaries.

MAIN MEASURES

Repetitive TBI was identified as a second TBI occurring at least 90 days after the first occurrence of TBI following an 18-month TBI-free period. We identified factors associated with repetitive TBI using a log-binomial model.

RESULTS

A total of 38 064 older Medicare beneficiaries experienced a TBI. Of these, 4562 (12%) beneficiaries sustained at least one subsequent TBI over up to 5 years of follow-up. The unadjusted incidence rate of repetitive TBI was 3022 (95% CI, 2935-3111) per 100 000 person-years. Epilepsy was the strongest predictor of repetitive TBI (relative risk [RR] = 1.44; 95% CI, 1.25-1.56), followed by Alzheimer disease and related dementias (RR = 1.32; 95% CI 1.20-1.45), and depression (RR = 1.30; 95% CI, 1.21-1.38).

CONCLUSIONS

Injury prevention and fall-reduction interventions could be targeted to identify groups of older adults at an increased risk of repetitive head injury. Future work should focus on injury-reduction initiatives to reduce the risk of repetitive TBI as well as assessment of outcomes related to repetitive TBI.

Scientific Evidences of Calorie Restriction and Intermittent Fasting for Neuroprotection in Traumatic Brain Injury Animal Models: A Review of the Literature

It has widely been accepted that food restriction (FR) without malnutrition has multiple health benefits. Various calorie restriction (CR) and intermittent fasting (IF) regimens have recently been reported to exert neuroprotective effects in traumatic brain injury (TBI) through variable mechanisms. However, the evidence connecting CR or IF to neuroprotection in TBI as well as current issues remaining in this research field have yet to be reviewed in literature. The objective of our review was therefore to weigh the evidence that suggests the connection between CR/IF with recovery promotion following TBI. Medline, Google Scholar and Web of Science were searched from inception to 25 February 2022. An overwhelming number of results generated suggest that several types of CR/IF play a promising role in promoting post-TBI recovery. This recovery is believed to be achieved by alleviating mitochondrial dysfunction, promoting hippocampal neurogenesis, inhibiting glial cell responses, shaping neural cell plasticity, as well as targeting apoptosis and autophagy. Further, we represent our views on the current issues and provide thoughts on the future direction of this research field.

Association of Preinjury Medical Diagnoses With Pediatric Persistent Postconcussion Symptoms in Electronic Health Records

OBJECTIVE

To identify risk factors and generate hypotheses for pediatric persistent postconcussion symptoms (PPCS).

SETTING

A regional healthcare system in the Southeastern United States.

PARTICIPANTS

An electronic health record-based algorithm was developed and validated to identify PPCS cases and controls from an institutional database of more than 2.8 million patients. PPCS cases (n = 274) were patients aged 5 to 18 years with PPCS-related diagnostic codes or with PPCS key words identified by natural language processing of clinical notes. Age, sex, and year of index event-matched controls (n = 1096) were patients with mild traumatic brain injury codes only. Patients with moderate or severe traumatic brain injury were excluded. All patients used our healthcare system at least 3 times 180 days before their injury.

DESIGN

Case-control study.

MAIN MEASURES

The outcome was algorithmic classification of PPCS. Exposures were all preinjury medical diagnoses assigned at least 180 days before the injury.

RESULTS

Cases and controls both had a mean of more than 9 years of healthcare system use preinjury. Of 221 preinjury medical diagnoses, headache disorder was associated with PPCS after accounting for multiple testing (odds ratio [OR] = 2.9; 95% confidence interval [CI]: 1.6-5.0; P = 2.1e-4). Six diagnoses were associated with PPCS at a suggestive threshold for statistical significance (false discovery rate P < .10): gastritis/duodenitis (OR = 2.8; 95% CI: 1.6-5.1; P = 5.0e-4), sleep disorders (OR = 2.3; 95% CI: 1.4-3.7; P = 7.4e-4), abdominal pain (OR = 1.6; 95% CI: 1.2-2.2; P = 9.2e-4), chronic sinusitis (OR = 2.8; 95% CI: 1.5-5.2; P = 1.3e-3), congenital anomalies of the skin (OR = 2.9; 95% CI: 1.5-5.5; P = 1.9e-3), and chronic pharyngitis/nasopharyngitis (OR = 2.4; 95% CI: 1.4-4.3; P = 2.5e-3).

CONCLUSIONS

These results support the strong association of preinjury headache disorders with PPCS. An association of PPCS with prior gastritis/duodenitis, sinusitis, and pharyngitis/nasopharyngitis suggests a role for chronic inflammation in PPCS pathophysiology and risk, although results could equally be attributable to a higher likelihood of somatization among PPCS cases. Identified risk factors should be investigated further and potentially considered during the management of pediatric mild traumatic brain injury cases.

Incidence of New Neuropsychiatric Disorder Diagnoses Following Traumatic Brain Injury

BACKGROUND

Neuropsychiatric disturbances (NPDs) are common following traumatic brain injury (TBI) and associated with poor recovery. Prior estimates of NPD following TBI failed to account for preexisting NPDs or potential confounding.

METHODS

We estimated the risk of anxiety, posttraumatic stress disorder (PTSD), bipolar disorder, and alcohol and substance dependence disorder diagnoses associated with TBI using administrative claims data from a large insurer in the United States, 2008-2014. We calculated rates of new NPD diagnoses during the 12 months before and 24 months after TBI and estimated the risk of NPD following TBI using a difference-in-difference approach and adjusting for confounders.

RESULTS

Before the TBI occurred, rates of NPD diagnoses were more than double in the TBI cohort (n = 207 354) relative to the no-TBI cohort (n = 414 708). TBI was associated with an increased risk of anxiety (rate ratio [RtR] = 1.08; 95% confidence interval [CI], 1.05-1.12) and PTSD (RtR = 1.41; 95% CI, 1.24-1.60) diagnoses. Rates of alcohol (RtR = 0.32; 95% CI, 0.30-0.34) and substance use disorder (RtR = 0.57; 95% CI, 0.55-0.59) diagnoses decreased following TBI.

CONCLUSIONS

In this large national study, rates of NPD were much higher among individuals with TBI than those in a non-TBI cohort, even before the TBI took place. TBI was associated with an increased risk of anxiety and PTSD diagnoses. Results from this study also suggest that individuals who sustain TBI have increased contact with the healthcare system during the months prior to injury, providing a window for intervention, especially for individuals diagnosed with alcohol dependence disorder.

Effects of Prescription Opioid Use on Traumatic Brain Injury Risk in Older Adults

OBJECTIVE

The objective of this study was to estimate the risk of traumatic brain injury (TBI) associated with opioid use among older adult Medicare beneficiaries.

SETTING

Five percent sample of Medicare administrative claims obtained for years 2011-2015.

PARTICIPANTS

A total of 50 873 community-dwelling beneficiaries 65 years and older who sustained TBI.

DESIGN

Case-crossover study comparing opioid use in the 7 days prior to TBI with the control periods of 3, 6, and 9 months prior to TBI.

MAIN MEASURES

TBI cases were identified using ICD-9 (International Classification of Diseases, Ninth Revision) and ICD-10 (International Classification of Diseases, Tenth Revision) codes. Prescription opioid exposure and concomitant nonopioid fall risk-increasing drug (FRID) use were determined by examining the prescription drug event file.

RESULTS

The 8257 opioid users (16.2%) were significantly younger (mean age 79.0 vs 80.8 years, P < .001). Relative to nonusers, opioid users were more likely to be women (77.0% vs 70.0%, P < .001) with a Charlson Comorbidity Index of 2 or more (43.7% vs 30.9%, P < .001) and higher concomitant FRID use (94.0% vs 82.7%, P < .001). Prescription opioid use independently increased the risk of TBI compared with nonusers (OR = 1.34; 95% CI, 1.28-1.40). In direct comparisons, we did not observe evidence of a significant difference in adjusted TBI risk between high- (≥90 morphine milligram equivalents) and standard-dose opioid prescriptions (OR = 1.01; 95% CI, 0.90-1.14) or between acute and chronic (≥90 days) opioid prescriptions (OR = 0.93; 95% CI, 0.84-1.02).

CONCLUSIONS

Among older adult Medicare beneficiaries, prescription opioid use independently increased risk for TBI compared with nonusers after adjusting for concomitant FRID use. We found no significant difference in adjusted TBI risk between high-dose and standard-dose opioid use, nor did we find a significant difference in adjusted TBI risk between acute and chronic opioid use. This analysis can inform prescribing of opioids to community-dwelling older adults for pain management.

Healthcare Utilization Following Traumatic Brain Injury in a Large National Sample

OBJECTIVE

To evaluate the impact of traumatic brain injury (TBI) on healthcare utilization (HCU) over a 1-year period in a large national sample of individuals diagnosed with TBI across multiple care settings.

SETTING

Commercial insurance enrollees.

PARTICIPANTS

Individuals with and without TBI, 2008-2014.

DESIGN

Retrospective cohort.

MAIN MEASURES

We compared the change in the 12-month sum of inpatient, outpatient, emergency department (ED), and prescription HCU from pre-TBI to post-TBI to the same change among a non-TBI control group. Most rehabilitation visits were not included. We stratified models by age ≥65 and included the month of TBI in subanalysis.

RESULTS

There were 207 354 individuals in the TBI cohort and 414 708 individuals in the non-TBI cohort. Excluding the month of TBI diagnosis, TBI resulted in a slight increase in outpatient visits (rate ratio [RtR] = 1.05; 95% confidence interval [CI], 1.04-1.06) but decrease in inpatient HCU (RtR = 0.86; 95% CI, 0.84-0.88). Including the month of TBI in the models resulted in increased inpatient (RtR = 1.55; 95% CI, 1.52-1.58) and ED HCU (RtR = 1.37; 95% CI, 1.34-1.40).

CONCLUSION

In this population of individuals who maintained insurance coverage following TBI, results suggest that TBI may have a limited impact on nonrehabilitation HCU at the population level.

Early Brain Injury and Adaptive Functioning in Middle Childhood: The Mediating Role of Pragmatic Language

OBJECTIVE

Traumatic brain injuries (TBIs) often adversely affect adaptive functioning (AF). However, the cognitive mechanisms by which AF is disrupted are not well understood in young children who sustain TBI. This study examined pragmatic language (PL) and executive functioning (EF) as potential mechanisms for AF disruption in children with early, predominantly mild-complicated, TBI.

METHOD

The sample consisted of 76 children between the ages of 6 and 10 years old who sustained a TBI (n = 36) or orthopedic injury (OI; n = 40) before 6 years of age and at least 1 year prior to testing (M = 4.86 years, SD = 1.59). Children's performance on a PL and an expressive vocabulary task (which served as a control task), and parent report of child's EF and AF were examined at two time points 1 year apart (i.e., at age 8 and at age 9 years).

RESULTS

Injury type (TBI vs. OI) significantly predicted child's social and conceptual, but not practical, AF. Results indicated that PL, and not expressive vocabulary or EF at time 1, mediated the relationship between injury type and both social and conceptual AF at time 2.

CONCLUSIONS

A TBI during early childhood appears to subtly, but uniquely, disrupt complex language skills (i.e., PL), which in turn may disrupt subsequent social and conceptual AF in middle childhood. Additional longitudinal research that examines different aspects of PL and adaptive outcomes into adolescence is warranted.

Development of a Predictive Algorithm to Identify Adults With Mobility Limitations Using VA Health Care Administrative Data

An estimated 31.5 million Americans have a mobility limitation. Health care administrative data could be a valuable resource for research on this population but methods for cohort identification are lacking. We developed and tested an algorithm to reliably identify adults with mobility limitation in U.S. Department of Veterans Affairs health care data. We linked diagnosis, encounter, durable medical equipment, and demographic data for 964 veterans to their self-reported mobility limitation from the Medicare Current Beneficiary Survey. We evaluated performance of logistic regression models in classifying mobility limitation. The binary approach (yes/no limitation) had good sensitivity (70%) and specificity (79%), whereas the multilevel approach did not perform well. The algorithms for predicting a binary mobility limitation outcome performed well at discriminating between veterans who did and did not have mobility limitation. Future work should focus on multilevel approaches to predicting mobility limitation and samples with greater proportions of women and younger adults.

Traumatic Brain Injury Incidence in Adults with Intellectual and Developmental Disabilities

BACKGROUND

In Ontario, there are approximately 66,000 adults living with a diagnosis of intellectual and developmental disabilities (IDD). These individuals are nearly twice as likely to experience an injury compared to the general population. Falls are an important contributor to injuries in persons with IDD and in the general population, and are consistently found to be the leading cause of traumatic brain injury (TBI). There is currently no literature that quantitatively examines TBI among persons with IDD. The purpose of this study was to compare the risk of TBI for adults with and without IDD in Ontario over time and by demographic information.

METHODS

Using administrative health databases, two main cohorts were identified: (1) adults with IDD, and (2) a random 10% sample of adults without IDD. Within each cohort, annual crude and adjusted incidence of TBI were calculated among unique individuals for each fiscal year from April 1, 2002 to March 31, 2017.

RESULTS

Over the 15-year study period, the average annual adjusted incidence of TBI was approximately 2.8 new cases per 1000 among Ontario adults with IDD, compared to approximately 1.53 per 1000 among those without IDD. In both cohorts, a higher proportion of TBI cases were younger (19-29 years) and male.

CONCLUSIONS

During the study period, persons with IDD experienced a significantly higher risk of TBI compared to the general population indicating the possibility, and need, for targeted TBI prevention.

Patterns of Psychotropic Medication Use among Individuals with Traumatic Brain Injury

The relationship between psychotropic medication use and traumatic brain injury (TBI) is not well understood. The objective of this study was to describe patterns of psychotropic medication use during the months before and after TBI and compare with a non-TBI cohort. We conducted a retrospective cohort study using administrative claims data for a commercially insured population from 2008 to 2014, and assessed monthly prevalence of psychotropic medication use by class before and after TBI (or matched index in the non-TBI controls). We tested time trends and quantified rates of increase using autoregressive models, and determined whether TBI impacted psychotropic medication use using difference-in-difference models. Compared with those without TBI (n = 414,708), individuals with TBI (n = 207,354) were more likely to receive any psychotropic medication both before (36.9% vs. 19.5%, p < 0.001) and after TBI (48.2% vs. 25.7%, p < 0.001). Prior to TBI, the rate of monthly increase in use of psychotropic medications in the TBI cohort was three to four times the rate observed in the non-TBI cohort, and was highest for antidepressants in both cohorts. After accounting for between-group and time trends, TBI was associated with increased use of several psychotropic medications including antipsychotics (rate ratio [RR] 1.08; 95% confidence interval [CI] 1.07, 1.09) and anxiolytics (RR 1.05; 95% CI 1.04, 1.06). Patterns of psychotropic medication use differed significantly between individuals with and without TBI. These results suggest that a better understanding of events leading up to and following TBI is needed to elucidate the role psychotropic medications play in the natural history of TBI.

Receipt of Treatment for Depression Following Traumatic Brain Injury

OBJECTIVE

Lack of evidence for efficacy and safety of treatment and limited clinical guidance have increased potential for undertreatment of depression following traumatic brain injury (TBI).

METHODS

We conducted a retrospective cohort study among individuals newly diagnosed with depression from 2008 to 2014 to assess the impact of TBI on receipt of treatment for incident depression using administrative claims data. We created inverse probability of treatment-weighted populations to evaluate the impact of TBI on time to receipt of antidepressants or psychotherapy following new depression diagnosis during 24 months post-TBI or matched index date (non-TBI cohort).

RESULTS

Of 10 428 individuals with incident depression in the TBI cohort, 44.7% received 1 or more antidepressants and 20.0% received 1 or more psychotherapy visits. Of 10 463 in the non-TBI cohort, 41.2% received 1 or more antidepressants and 17.6% received 1 or more psychotherapy visits. TBI was associated with longer time to receipt of antidepressants compared with the non-TBI cohort (average 39.6 days longer than the average 126.2 days in the non-TBI cohort; 95% confidence interval [CI], 24.6-54.7). Longer time to psychotherapy was also observed among individuals with TBI at 6 months post-TBI (average 17.1 days longer than the average 47.9 days in the non-TBI cohort; 95% CI, 4.2-30.0), although this association was not significant at 12 and 24 months post-TBI.

CONCLUSIONS

This study raises concerns about the management of depression following TBI.

Sleep disturbances among older adults following traumatic brain injury

Sleep disturbances are common sequelae of traumatic brain injury (TBI) that are associated with poorer recovery. This is important among older adults, who fare worse following TBI relative to younger adults and have a higher prevalence of sleep disorders. The objective of this study was to assess the risk of newly-diagnosed sleep disorders following TBI among adults ≥65 years. Using a large commercial insurance database, older adults diagnosed with TBI between 2008-2014 (n = 78,044) and non-TBI controls (n = 76,107) were identified. The first dates of diagnosis of four common sleep disorders (hypersomnia, insomnia, obstructive sleep apnea, and restless legs syndrome) and a composite of any sleep disorder were identified. To compare groups, this study used a difference-in-differences (DID) approach, accounting for pre-index differences between cohorts and the trends in sleep diagnoses over time. Individuals with TBI were more likely to have any newly-diagnosed sleep disorder before (14.1% vs 9.4%, p < 0.001) and after (22.7% vs 14.1%, p < 0.001) the index date. In fully adjusted DID models, TBI was associated with an increased risk of insomnia (rate ratio (RR) = 1.17; 95% confidence interval (CI) = 1.08-1.26) and any sleep disorder (RR = 1.13; 95% CI = 1.08-1.19). Following TBI among older adults, screening and education on sleep disorders should be considered.

Association Between Statin Use and Risk of Dementia After a Concussion

Importance

Concussions are an acute injury that may lead to chronic disability, while statin use might improve neurologic recovery.

Objective

To test whether statin use is associated with an increased or decreased risk of subsequent dementia after a concussion.

Design, Setting, and Participants

Large extended population-based double cohort study in Ontario, Canada, from April 1, 1993, to April 1, 2013 (enrollment), and continued until March 31, 2016 (follow-up). Dates of analysis were April 28, 2014, through March 21, 2019. Participants were older adults diagnosed as having a concussion, excluding severe cases resulting in hospitalization, individuals with a prior diagnosis of dementia or delirium, and those who died within 90 days.

Exposure

Statin prescription within 90 days after a concussion.

Main Outcome and Measure

Long-term incidence of dementia.

Results

This study identified 28 815 patients diagnosed as having a concussion (median age, 76 years; 61.3% female), of whom 7058 (24.5%) received a statin, and 21 757 (75.5%) did not receive a statin. A total of 4727 patients subsequently developed dementia over a mean follow-up of 3.9 years, equal to an incidence of 1 case per 6 patients. Patients who received a statin had a 13% reduced risk of dementia compared with patients who did not receive a statin (relative risk, 0.87; 95% CI, 0.81-0.93; P < .001). The decreased risk of dementia associated with statin use applied to diverse patient groups, remained independent of other cardiovascular medication use, intensified over time, was distinct from the risk of subsequent depression, and was not observed in patients after an ankle sprain.

Conclusions and Relevance

In this study, older adults had a substantial long-term risk of dementia after a concussion, which was associated with a modest reduction among patients receiving a statin.

Sex Differences in In-hospital Complications Among Older Adults After Traumatic Brain Injury

BACKGROUND

Older adults have the highest rates of hospitalization and mortality after traumatic brain injury (TBI) and suffer poorer outcomes compared with younger adults with similar injuries. Non-neurological complications can significantly impact outcomes. Evidence suggests that women may have better outcomes after TBI. However, sex differences in in-hospital complications among older adults after TBI have not been studied. The objective of this study was to assess sex differences in in-hospital complications after TBI among adults aged 65 y and older.

METHODS

We conducted a retrospective cohort study of adults aged ≥65 y treated for isolated moderate to severe TBI at the R Adams Cowley Shock Trauma Center between 1996 and 2012. Using the Shock Trauma Center registry, we identified TBI using the International Classification of Disease, Ninth Revision, Clinical Modification codes and required an abbreviated injury scale head score ≥3, abbreviated injury scale scores for other body regions ≤2, and a blunt injury mechanism. We searched the Shock Trauma Center registry for the International Classification of Disease, Ninth Revision, Clinical Modification codes representing in-hospital complications.

RESULTS

Of 2511 patients meeting inclusion criteria, 1283 (51.1%) were men and 635 (25.1%) developed an in-hospital complication. Men were more likely than women to develop an in-hospital complication (28.1% versus 22.0, P < 0.001). In an adjusted analysis, men were at increased risk of any in-hospital complication (hazards ratio 1.23; 95% confidence interval 1.05, 1.44) compared with women.

CONCLUSIONS

Older men were more likely to have any in-hospital complications than women.

Diagnostic Algorithms to Study Post-Concussion Syndrome Using Electronic Health Records: Validating a Method to Capture an Important Patient Population

Post-concussion syndrome (PCS) is characterized by persistent cognitive, somatic, and emotional symptoms after a mild traumatic brain injury (mTBI). Genetic and other biological variables may contribute to PCS etiology, and the emergence of biobanks linked to electronic health records (EHRs) offers new opportunities for research on PCS. We sought to validate the EHR data of PCS patients by comparing two diagnostic algorithms deployed in the Vanderbilt University Medical Center de-identified database of 2.8 million patient EHRs. The algorithms identified individuals with PCS by: 1) natural language processing (NLP) of narrative text in the EHR combined with structured demographic, diagnostic, and encounter data; or 2) coded billing and procedure data. The predictive value of each algorithm was assessed, and cases and controls identified by each approach were compared on demographic and medical characteristics. The NLP algorithm identified 507 cases and 10,857 controls. The negative predictive value in controls was 78% and the positive predictive value (PPV) in cases was 82%. Conversely, the coded algorithm identified 1142 patients with two or more PCS billing codes and had a PPV of 76%. Comparisons of PCS controls to both case groups recovered known epidemiology of PCS: cases were more likely than controls to be female and to have pre-morbid diagnoses of anxiety, migraine, and post-traumatic stress disorder. In contrast, controls and cases were equally likely to have attention deficit hyperactive disorder and learning disabilities, in accordance with the findings of recent systematic reviews of PCS risk factors. We conclude that EHRs are a valuable research tool for PCS. Ascertainment based on coded data alone had a predictive value comparable to an NLP algorithm, recovered known PCS risk factors, and maximized the number of included patients.

Patient Presentations in Outpatient Settings: Epidemiology of Adult Head Trauma Treated Outside of Hospital Emergency Departments

BACKGROUND

While deaths, hospitalizations, and emergency department visits for head trauma are well understood, little is known about presentations in outpatient settings. Our objective was to examine the epidemiology and extent of healthcare-seeking adult (18-64 years) head trauma patients presenting in outpatient settings compared with patients receiving nonhospitalized emergency department care.

METHODS

We used 2004-2013 MarketScan Medicaid/commercial claims to identify head trauma patients managed in outpatient settings (primary care provider, urgent care) and the emergency department. We examined differences in demographic and injury-specific factors, Centers for Disease Control and Prevention-defined head trauma diagnoses, and extent of and reasons for postindex visit ambulatory care use within 30/90/180 days by index visit location, as well as annual and monthly variations in head trauma trends. We used outpatient incidence rates to estimate the US nationwide outpatient burden.

RESULTS

A total of 1.19 million index outpatient visits were included (emergency department: 348,659). Nationwide, they represented a weighted annual burden of 1.16 million index outpatient cases. These encompassed 46% of all known healthcare-seeking head trauma in 2013 (outpatient/emergency department/inpatient/fatalities) and increased in magnitude (+31%) from 2004 to 2013. One fourth (27%) of office/clinic visits led to diagnosis with concussion on index presentation (urgent care: 32%). Distributions of demographic factors varied with index visit location while injury-specific factors were largely comparable. Subsequent visits reflected high demand for follow-up treatment, increased concussive diagnoses, and sequelae-associated care.

CONCLUSIONS

Adult outpatient presentations of head trauma remain poorly understood. The results of this study demonstrate the extensive magnitude of their occurrence and close association with need for follow-up care.

Accuracy of Administrative Health Data for Surveillance of Traumatic Brain Injury: A Bayesian Latent Class Analysis

BACKGROUND

Traumatic brain injury surveillance provides information for allocating resources to prevention efforts. Administrative data are widely available and inexpensive but may underestimate traumatic brain injury burden by misclassifying cases. Moreover, previous studies evaluating the accuracy of administrative data surveillance case definitions were at risk of bias by using imperfect diagnostic definitions as reference standards. We assessed the accuracy (sensitivity/specificity) of traumatic brain injury surveillance case definitions in administrative data, without using a reference standard, to estimate incidence accurately.

METHODS

We used administrative data from a 25% random sample of Montreal residents from 2000 to 2014. We used hierarchical Bayesian latent class models to estimate the accuracy of widely used traumatic brain injury case definitions based on the International Classification of Diseases, or on head radiologic examinations, covering the full injury spectrum in children, adults, and the elderly. We estimated measurement error-adjusted age- and severity-specific incidence.

RESULTS

The adjusted traumatic brain injury incidence was 76 (95% CrI = 68, 85) per 10,000 person-years (underestimated as 54 [95% CrI = 54, 55] per 10,000 without adjustment). The most sensitive case definitions were radiologic examination claims in adults/elderly (0.48; 95% CrI = 0.43, 0.55 and 0.66; 95% CrI = 0.54, 0.79) and emergency department claims in children (0.45; 95% CrI = 0.39, 0.52). The most specific case definitions were inpatient claims and discharge abstracts (0.99; 95% CrI = 0.99, 1.00). We noted strong secular trends in case definition accuracy.

CONCLUSIONS

Administrative data remain a useful tool for conducting traumatic brain injury surveillance and epidemiologic research when measurement error is adjusted for.

The Epidemiology of Pediatric Head Injury Treated Outside of Hospital Emergency Departments

BACKGROUND

Although head trauma-related deaths, hospitalizations, and emergency department visits are well characterized, few studies describe pediatric patients presenting outside of emergency departments. We compared the epidemiology and extent of healthcare-seeking pediatric (0-17 years) patients presenting in outpatient settings with those of patients seeking nonhospitalized emergency department care.

METHODS

We used MarketScan Medicaid and commercial claims, 2004-2013, to identify patients managed in two outpatient settings (physician's offices/clinics, urgent care) and the emergency department. We then examined differences in demographic and injury-specific factors, Centers for Disease Control and Prevention-defined head trauma diagnoses, the extent of and reasons for post-index visit ambulatory care use within 30/90/180 days, and annual and monthly variations in head trauma trends. Outpatient incidence rates in 2013 provided estimates of the nationwide US outpatient burden.

RESULTS

A total of 1,683,097 index visits were included, representing a nationwide burden in 2013 of 844,660 outpatient cases, a number that encompassed 51% of healthcare-seeking head trauma that year and that substantially increased in magnitude from 2004 to 2013. Two-thirds (68%) were managed in outpatient settings. While demographic distributions varied with index-visit location, injury-specific factors were comparable. Seasonal spikes appeared to coincide with school sports.

CONCLUSIONS

There is an urgent need to better understand the natural history of head trauma in the >800,000 pediatric patients presenting each year for outpatient care. These outpatient injuries, which are more than double the number of head trauma cases recorded in the hospital-affiliated settings, illustrate the potential importance of expanding inclusion criteria in surveillance and prevention efforts designed to address this critical issue.

Bleeding and Thromboembolism After Traumatic Brain Injury in the Elderly: A Real Conundrum

BACKGROUND

Elderly patients presenting with a traumatic brain injury (TBI) often have comorbidities that increase risk of thromboembolic (TE) disease and recurrent TBI. A significant number are on anticoagulant therapy at the time of injury and studies suggest that continuing anticoagulation can prevent TE events. Understanding bleeding, recurrent TBI, and TE risk after TBI can help to guide therapy. Our objectives were to 1) evaluate the incidence of bleeding, recurrent TBI, and TE events after an initial TBI in older adults and 2) identify which factors contribute to this risk.

METHODS

Retrospective analysis of Medicare claims between May 30, 2006 and December 31, 2009 for patients hospitalized with TBI was performed. We defined TBI for the index admission, and hemorrhage (gastrointestinal bleeding or hemorrhagic stroke), recurrent TBI, and TE events (stroke, myocardial infarction, deep venous thrombosis, or pulmonary embolism) over the following year using ICD-9 codes. Unadjusted incidence rates and 95% confidence intervals (CIs) were calculated. Risk factors of these events were identified using logistic regression.

RESULTS

Among beneficiaries hospitalized with TBI, incidence of TE events (58.6 events/1000 person-years; 95% CI 56.2, 60.8) was significantly higher than bleeding (23.6 events/1000 person-years; 95% CI 22.2, 25.1) and recurrent TBI events (26.0 events/1000 person-years; 95% CI 24.5, 27.6). Several common factors predisposed to bleeding, recurrent TBI, and TE outcomes.

CONCLUSIONS

Among Medicare patients hospitalized with TBI, the incidence of TE was significantly higher than that of bleeding or recurrent TBI. Specific risk factors of bleeding and TE events were identified which may guide care of older adults after TBI.

Safety of Antidepressant Classes Used Following Traumatic Brain Injury Among Medicare Beneficiaries: A Retrospective Cohort Study

OBJECTIVE

There is poor evidence supporting the use of any pharmacologic treatments for neuropsychiatric disorders following traumatic brain injury (TBI), especially among older adults. Informed by our recent characterization of psychotropic medication use among Medicare beneficiaries with TBI, the objective of this study was to compare the risk of several adverse events associated with use of the three most commonly used classes of antidepressants following TBI in this population.

METHODS

We conducted a retrospective cohort study using administrative claims data from US Medicare beneficiaries hospitalized with TBI between 2006 and 2010 (n = 30,886). We assessed monthly selective serotonin reuptake inhibitor (SSRI), serotonin-norepinephrine reuptake inhibitor (SNRI), and tricyclic antidepressant (TCA) use. We identified adverse events associated with these drug classes that were available in administrative claims data from studies in TBI and non-TBI populations: seizures, hemorrhagic stroke, ischemic stroke, gastrointestinal bleed, hyponatremia, and fractures. We made comparisons between antidepressant classes to assess excess risk of each adverse event using discrete time analysis and controlling for potential confounders.

RESULTS

SSRIs were the most commonly used of the antidepressant classes, followed by SNRIs and TCAs. We observed a total of 23,021 adverse events. Ischemic stroke was the most frequent (8296 events). Hemorrhagic stroke (1706 events) and seizures (1841) were least often observed. Compared with TCAs, SSRI use was associated with an increased risk of hemorrhagic stroke (risk ratio 2.47; 95% confidence interval 1.30-4.70). No other antidepressant class comparisons were associated with increased risk of adverse events.

CONCLUSION

Compared with SSRIs, use of SNRIs and TCAs following hospitalization for TBI among Medicare beneficiaries was not associated with an increased risk of any of the studied adverse events. Compared to TCAs, SSRI use was associated with increased risk of hemorrhagic stroke. This information may help guide patients and prescribers in selecting antidepressants for older adults following TBI.

Treatment Charges for Traumatic Brain Injury Among Older Adults at a Trauma Center

OBJECTIVE

To provide charge estimates of treatment for traumatic brain injury (TBI), including both hospital and physician charges, among adults 65 years and older treated at a trauma center.

METHODS

We identified older adults treated for TBI during 2008-2012 (n = 1843) at Maryland's Primary Adult Resource Center and obtained hospital and physician charges separately. Analyses were stratified by sex and all charges were inflated to 2012 dollars. Total TBI charges were modeled as a function of covariates using a generalized linear model.

RESULTS

Women comprised 48% of the sample. The mean unadjusted total TBI hospitalization charge for adults 65 years and older was $36 075 (standard deviation, $63 073). Physician charges comprised 15% of total charges. Adjusted mean charges were lower in women than in men (adjusted difference, -$894; 95% confidence interval, -$277 to -$1512). Length of hospital and intensive care unit stay were associated with the highest charges.

CONCLUSIONS

This study provides the first estimates of hospital and physician charges associated with hospitalization for TBI among older adults at a trauma center that will aid in resource allocation, triage decisions, and healthcare policy.

Prevalence of a definitive airway in patients with severe traumatic brain injury received at four urban public university hospitals in India: a cohort study

AIM

To estimate the proportion of patients arriving with a Glasgow Coma Scale (GCS) less than 9 who had a definitive airway placed prior to arrival.

METHODS

We conducted a retrospective analysis of the data from a multicentre, prospective observational research project entitled Towards Improved Trauma Care Outcomes in India. Adults aged ≥18 years with an isolated traumatic brain injury (TBI) who were transferred from another hospital to the emergency department of the participating hospital with a GCS less than 9 were included. Our outcome was a definitive airway, defined as either intubation or surgical airway, placed prior to arrival at a participating centre.

RESULTS

The total number of patients eligible for this study was 1499. The median age was 40 years and 84% were male. Road traffic injuries and falls comprised 88% of the causes of isolated TBI. The number of patients with GCS<9 who had a definitive airway placed before reaching the participating centres was 229. Thus, the proportion was 0.15 (95% CI 0.13 to 0.17). The proportions of patients with a definitive airway who arrived after 24 hours (19%) were approximately double the proportion of patients who arrived within 6 hours (10%) after injury to the definitive care centre.

CONCLUSION

The rates of definitive airway placement are poor in adults with an isolated TBI who have been transferred from another health facility to tertiary care centres in India.

Severely Elevated Blood Pressure and Early Mortality in Children with Traumatic Brain Injuries: The Neglected End of the Spectrum

Introduction

In adults with traumatic brain injuries (TBI), hypotension and hypertension at presentation are associated with mortality. The effect of age-adjusted blood pressure in children with TBI has been insufficiently studied. We sought to determine if age-adjusted hypertension in children with severe TBI is associated with mortality.

Methods

This was a retrospective analysis of the Department of Defense Trauma Registry (DoDTR) between 2001 and 2013. We included for analysis patients <18 years with severe TBI defined as Abbreviated Injury Severity (AIS) scores of the head ≥3. We defined hypertension as moderate for systolic blood pressures (SBP) between the 95^th and 99^th percentile for age and gender and severe if greater than the 99th percentile. Hypotension was defined as SBP <90 mmHg for children >10 years or < 70mmHg + (2 × age) for children ≤10 years. We performed multivariable logistic regression and Cox regression to determine if BP categories were associated with mortality.

Results

Of 4,990 children included in the DoDTR, 740 met criteria for analysis. Fifty patients (6.8%) were hypotensive upon arrival to the ED, 385 (52.0%) were normotensive, 115 (15.5%) had moderate hypertension, and 190 (25.7%) had severe hypertension. When compared to normotensive patients, moderate and severe hypertension patients had similar Injury Severity Scores, similar AIS head scores, and similar frequencies of neurosurgical procedures. Multivariable logistic regression demonstrated that hypotension (odd ratio [OR] 2.85, 95 confidence interval [CI] 1.26–6.47) and severe hypertension (OR 2.58, 95 CI 1.32–5.03) were associated with increased 24-hour mortality. Neither hypotension (Hazard ratio (HR) 1.52, 95 CI 0.74–3.11) nor severe hypertension (HR 1.65, 95 CI 0.65–2.30) was associated with time to mortality.

Conclusion

Pediatric age-adjusted hypertension is frequent after severe TBI. Severe hypertension is strongly associated with 24-hour mortality. Pediatric age-adjusted blood pressure needs to be further evaluated as a critical marker of early mortality.

Is Concussion a Risk Factor for Epilepsy?

Background: Epidemiologic studies have suggested that concussion, or mild traumatic brain injury (mTBI), is associated with a twofold or greater increase in relative risk for the development of post-traumatic epilepsy. To assess the clinical validity of these findings, we analyzed the incidence of epilepsy in a large cohort of post-concussion patients in whom concussion was strictly defined according to international guidelines. Methods: A retrospective cohort study of 330 consecutive post-concussion patients followed by a single concussion specialist. Exclusion criteria: abnormal brain CT/MRI, Glasgow Coma Scale<13 more than 1-hour post-injury, hospitalization >48 hours. Independent variable: concussion. Outcome measure: epilepsy incidence (dependent variable). Results: The mean number of concussions/patient was 3.3 (±2.5), mean age at first clinic visit 28 years (±14.7), and mean follow-up after first concussion 7.6 years (±10.8). Eight patients were identified whose medical records included mention of seizures or convulsions or epilepsy. Upon review by an epileptologist none met criteria for a definite diagnosis of epilepsy: four had episodic symptoms incompatible with epileptic seizures (e.g., multifocal paraesthesiae, multimodality hallucinations, classic migraine) and normal EEG/MRI investigations; four had syncopal (n=2) or concussive (n=2) convulsions. Compared with annual incidence (0.5/1000 individuals) in the general population, there was no difference in this post-concussion cohort (p=0.49). Conclusion: In this large cohort of post-concussion patients we found no increased incidence of epilepsy. For at least the first 5-10 years post-injury, concussion/mTBI should not be considered a significant risk factor for epilepsy. In patients with epilepsy and a past history of concussion, the epilepsy should not be presumed to be post-traumatic.

Risk of Stroke Among Older Medicare Antidepressant Users With Traumatic Brain Injury

OBJECTIVE

To estimate the risk of stroke associated with new antidepressant use among older adults with traumatic brain injury (TBI).

PARTICIPANTS

A total of 64 214 Medicare beneficiaries aged 65 years or older meeting inclusion criteria and hospitalized with a TBI during 2006 to 2010.

DESIGN

New user design. Generalized estimating equations were used to estimate the relative risks (RRs) of stroke.

MAIN MEASURES

Primary exposure was new antidepressant use following TBI identified through Medicare part D claims. The primary outcome was stroke following TBI. Ischemic and hemorrhagic strokes were secondary outcomes.

RESULTS

A total of 20 859 (32%) beneficiaries used an antidepressant at least once following TBI. Selective serotonin reuptake inhibitors accounted for the majority of antidepressant use. Selective serotonin reuptake inhibitor use was associated with an increased risk of hemorrhagic stroke (RR, 1.26; 95% confidence interval [CI], 1.06-1.50) but not ischemic stroke (RR, 1.04; 95% CI, 0.94-1.15). The selective serotonin reuptake inhibitors escitalopram (RR, 1.33; 95% CI, 1.02-1.74) and sertraline (RR, 1.46; 95% CI, 1.10-1.94) were associated with an increase in the risk of hemorrhagic stroke.

CONCLUSION

Findings from this study will aid prescribers in choosing appropriate antidepressants to treat depression in older adults with TBI.

Association of Alcohol With Mortality After Traumatic Brain Injury

Although alcohol exposure results in reduced mortality after traumatic brain injury (TBI) in animal models, clinical trials based on proposed mechanisms have been disappointing and have reported conflicting results. Methodological issues common to many of these clinical studies may have contributed to the spurious results. Our objective was to evaluate the association between blood alcohol concentration (BAC) and in-hospital mortality after TBI, and overcome methodological problems of prior studies. We conducted a retrospective cohort study on individuals treated for isolated TBI (n = 1,084) at the R Adams Cowley Shock Trauma Center (Baltimore, Maryland) from 1997 to 2012. We excluded individuals with injury to other body regions and examined multiple cutpoints of BAC. Our primary outcome was in-hospital mortality. In adjusted logistic regression models, the upper level of each blood alcohol categorization from 0.10 g/dL (odds ratio = 0.63, 95% confidence interval: 0.40, 0.97) through 0.30 g/dL (odds ratio = 0.25, 95% confidence interval: 0.08, 0.84) was associated with reduced risk of mortality after TBI compared with individuals with undetectable BAC. In sensitivity analyses among individuals without penetrating brain injuries (95% firearm-related) (n = 899), the protective association was eliminated. This study provides evidence that the observed protective association between BAC and in-hospital mortality after TBI resulted from bias introduced by inclusion of penetrating injuries.

Traumatic brain injury in the prodromal period of Parkinson's disease: A large epidemiological study using medicare data

OBJECTIVE

Studies suggest a greater risk of Parkinson's disease (PD) after traumatic brain injury (TBI), but it is possible that the risk of TBI is greater in the prodromal period of PD. We aimed to examine the time-to-TBI in PD patients in their prodromal period compared to population-based controls.

METHODS

We identified 89,790 incident PD cases and 118,095 comparable controls aged > 65 years in 2009 using Medicare claims data. Using data from the preceding 5 years, we compared time-to-TBI in PD patients in their prodromal period to controls. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for TBI in a Cox regression, while adjusting for age, sex, race/ethnicity, modified Charlson comorbidity index, smoking, and alcohol use.

RESULTS

Risk of TBI was greater in PD patients in their prodromal period across all age and sex groups, with HRs consistently increasing with proximity to PD diagnosis. HRs ranged from 1.64 (95% CI, 1.52, 1.77) 5 years preceding diagnosis to 3.93 (95% CI, 3.74, 4.13) in the year before. The interaction between PD, TBI, and time was primarily observed for TBI attributed to falls. Motor dysfunction and cognitive impairment, suggested by corresponding International Classification of Diseases, Ninth Revision codes, partially mediated the PD-TBI association.

INTERPRETATION

There is a strong association between PD and a recent TBI in the prodromal period of PD. This association strengthens as PD diagnosis approaches and may be a result of undetected nonmotor and motor symptoms, but confirmation will be required. Ann Neurol 2017;82:744-754.

Head injuries (TBI) to adults and children in motor vehicle crashes

PURPOSE

This is a descriptive study. It determined the annual, national incidence of head injuries (traumatic brain injury, TBI) to adults and children in motor vehicle crashes. It evaluated NASS-CDS for exposure and incidence of various head injuries in towaway crashes. It evaluated 3 health databases for emergency department (ED) visits, hospitalizations, and deaths due to TBI in motor vehicle occupants.

METHODS

Four databases were evaluated using 1997-2010 data on adult (15+ years old) and child (0-14 years old) occupants in motor vehicle crashes: (1) NASS-CDS estimated the annual incidence of various head injuries and outcomes in towaway crashes, (2) National Hospital Ambulatory Medical Care Survey (NHAMCS)-estimated ED visits for TBI, (3) National Hospital Discharge Survey (NHDS) estimated hospitalizations for TBI, and (4) National Vital Statistics System (NVSS) estimated TBI deaths. The 4 databases provide annual national totals for TBI related injury and death in motor vehicle crashes based on differing definitions with TBI coded by the Abbreviated Injury Scale (AIS) in NASS-CDS and by International Classification of Diseases (ICD) in the health data.

RESULTS

Adults: NASS-CDS had 16,980 ± 2,411 (risk = 0.43 ± 0.06%) with severe head injury (AIS 4+) out of 3,930,543 exposed adults in towaway crashes annually. There were 49,881 ± 9,729 (risk = 1.27 ± 0.25%) hospitalized with AIS 2+ head injury, without death. There were 6,753 ± 882 (risk = 0.17 ± 0.02%) fatalities with a head injury cause. The public health data had 89,331 ± 6,870 ED visits, 33,598 ± 1,052 hospitalizations, and 6,682 ± 22 deaths with TBI. NASS-CDS estimated 48% more hospitalized with AIS 2+ head injury without death than NHDS occupants hospitalized with TBI. NASS-CDS estimated 29% more deaths with AIS 3+ head injury than NVSS occupant TBI deaths but only 1% more deaths with a head injury cause. Children: NASS-CDS had 1,453 ± 318 (risk = 0.32 ± 0.07%) with severe head injury (AIS 4+) out of 454,973 exposed children annually. There were 2,581 ± 683 (risk = 0.57 ± 0.15%) hospitalized with AIS 2+ head injury, without death. There were 466 ± 132 (risk = 0.10 ± 0.03%) fatalities with a head injury cause. The public health data had 19,251 ± 2,803 ED visits, 3,363 ± 255 hospitalizations, and 488 ± 6 deaths with TBI. NASS-CDS estimated 24% fewer hospitalized children with AIS 2+ head injury without death than NHDS hospitalization with TBI. NASS-CDS estimated 31% more deaths with AIS 3+ head injury than NVSS child deaths but 5% fewer deaths with a head injury cause.

CONCLUSIONS

The annual national incidence of motor vehicle-related head injury (TBI) was estimated using 1997-2010 NASS-CDS from the Department of Transportation and NHAMCS (ED visits), NHDS (hospitalizations), and NVSS (deaths) from the Department of Health and Human Services. The transportation and health databases use different definitions and coding, which complicates direct comparisons. Future work is needed where ICD to AIS translators are used if comparisons of serious head injuries in NASS and health data sets are to be made.

Implementation of the Canadian CT Head Rule and Its Association With Use of Computed Tomography Among Patients With Head Injury

STUDY OBJECTIVE

Approximately 1 in 3 computed tomography (CT) scans performed for head injury may be avoidable. We evaluate the association of implementation of the Canadian CT Head Rule on head CT imaging in community emergency departments (EDs).

METHODS

We conducted an interrupted time-series analysis of encounters from January 2014 to December 2015 in 13 Southern California EDs. Adult health plan members with a trauma diagnosis and Glasgow Coma Scale score at ED triage were included. A multicomponent intervention included clinical leadership endorsement, physician education, and integrated clinical decision support. The primary outcome was the proportion of patients receiving a head CT. The unit of analysis was ED encounter, and we compared CT use pre- and postintervention with generalized estimating equations segmented logistic regression, with physician as a clustering variable. Secondary analysis described the yield of identified head injuries pre- and postintervention.

RESULTS

Included were 44,947 encounters (28,751 preintervention and 16,196 postintervention), resulting in 14,633 (32.6%) head CTs (9,758 preintervention and 4,875 postintervention), with an absolute 5.3% (95% confidence interval [CI] 2.5% to 8.1%) reduction in CT use postintervention. Adjusted pre-post comparison showed a trend in decreasing odds of imaging (odds ratio 0.98; 95% CI 0.96 to 0.99). All but one ED reduced CTs postintervention (0.3% to 8.7%, one ED 0.3% increase), but no interaction between the intervention and study site over time existed (P=.34). After the intervention, diagnostic yield of CT-identified intracranial injuries increased by 2.3% (95% CI 1.5% to 3.1%).

CONCLUSION

A multicomponent implementation of the Canadian CT Head Rule was associated with a modest reduction in CT use and an increased diagnostic yield of head CTs for adult trauma encounters in community EDs.

Performance of International Classification of Diseases-based injury severity measures used to predict in-hospital mortality and intensive care admission among traumatic brain-injured patients

BACKGROUND

The International Classification of Diseases (ICD) is the main classification system used for population-based traumatic brain injury (TBI) surveillance activities but does not contain direct information on injury severity. International Classification of Diseases-based injury severity measures can be empirically derived or mapped to the Abbreviated Injury Scale, but no single approach has been formally recommended for TBI.

OBJECTIVE

The aim of this study was to compare the accuracy of different ICD-based injury severity measures for predicting in-hospital mortality and intensive care unit (ICU) admission in TBI patients.

METHODS

We conducted a population-based retrospective cohort study. We identified all patients 16 years or older with a TBI diagnosis who received acute care between April 1, 2006, and March 31, 2013, from the Quebec Hospital Discharge Database. The accuracy of five ICD-based injury severity measures for predicting mortality and ICU admission was compared using measures of discrimination (area under the receiver operating characteristic curve [AUC]) and calibration (calibration plot and the Hosmer-Lemeshow goodness-of-fit statistic).

RESULTS

Of 31,087 traumatic brain-injured patients in the study population, 9.0% died in hospital, and 34.4% were admitted to the ICU. Among ICD-based severity measures that were assessed, the multiplied derivative of ICD-based Injury Severity Score (ICISS-Multiplicative) demonstrated the best discriminative ability for predicting in-hospital mortality (AUC, 0.858; 95% confidence interval, 0.852-0.864) and ICU admissions (AUC, 0.813; 95% confidence interval, 0.808-0.818). Calibration assessments showed good agreement between observed and predicted in-hospital mortality for ICISS measures. All severity measures presented high agreement between observed and expected probabilities of ICU admission for all deciles of risk.

CONCLUSIONS

The ICD-based injury severity measures can be used to accurately predict in-hospital mortality and ICU admission in TBI patients. The ICISS-Multiplicative generally outperformed other ICD-based injury severity measures and should be preferred to control for differences in baseline characteristics between TBI patients in surveillance activities or injury research when only ICD codes are available.

LEVEL OF EVIDENCE

Prognostic study, level III.

Sex differences in mortality following isolated traumatic brain injury among older adults

BACKGROUND

Older adults have the highest rates of hospitalization and mortality from traumatic brain injury (TBI), yet outcomes in this population are not well studied. In particular, contradictory reports on the protective effect of female sex on mortality following TBI may have been related to age differences in TBI and other injury severity and mechanism. The objective of this study was to determine if there are sex differences in mortality following isolated TBI among older adults and compare with findings using all TBI. A secondary objective was to characterize TBI severity and mechanism by sex in this population.

METHODS

This was a retrospective cohort study conducted among adults aged 65 and older treated for TBI at a single large Level I trauma center from 1996 to 2012 (n = 4,854). Individuals treated for TBI were identified using International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Isolated TBI was defined as an Abbreviated Injury Scale score of 0 for other body regions. Our primary outcome was mortality at discharge.

RESULTS

Among those with isolated TBI (n = 1,320), women (45% of sample) were older (mean [SD], 78.9 [7.7] years) than men (76.8 [7.5] years) (p < 0.001). Women were more likely to have been injured in a fall (91% vs. 84%; p < 0.001). Adjusting for multiple injury severity measures, female sex was not significantly associated with decreased odds of mortality following isolated TBI (odds ratio, 1.01; 95% confidence interval, 0.66-1.54). Using all TBI cases, adjusted analysis found that female sex was significantly associated with decreased odd of mortality (odds ratio, 0.73; 95% confidence interval, 0.59-0.89).

CONCLUSION

We found no sex differences in mortality following isolated TBI among older adults, in contrast with other studies and our own analyses using all TBI cases. Researchers should consider isolated TBI in outcome studies to prevent residual confounding by severity of other injuries.

LEVEL OF EVIDENCE

Prognostic/epidemiologic study, level IV.

Differential protective effects of motorcycle helmets against head injury

BACKGROUND

Although numerous observational studies have demonstrated a protective effect of motorcycle helmets against head injury, the degree of protection against specific head injury types remains unclear. Experimental biomechanics studies involving cadavers, animals, and computer models have established that head injuries have varying etiologies. This retrospective cross-sectional study compared helmet protection against skull fracture, cerebral contusion, intracranial hemorrhage, and cerebral concussion in a consecutive series of motorcycle operators involved in recent traffic crashes in Kentucky.

METHODS

Police collision reports linked to hospital inpatient and emergency department (ED) claims were analyzed for the period 2008 to 2012. Motorcycle operators with known helmet use who were not killed at the crash scene were included in the study. Helmet use was ascertained from the police report. Skull fracture, cerebral contusion, intracranial hemorrhage, and cerebral concussion were identified from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes on the claims records. The relative risks of each type of head injury for helmeted versus unprotected operators were estimated using generalized estimating equations.

RESULTS

Helmets offer substantial protection against skull fracture (relative risk [RR] = 0.31, 95% confidence interval [CI], 0.23, 0.34), cerebral contusion (RR = 0.29, 95% CI, 0.16, 0.53), and intracranial hemorrhage (RR = 0.47, 95% CI, 0.35, 0.63). The findings pertaining to uncomplicated concussion (RR = 0.80, 95% CI, 0.64, 1.01) were inconclusive. A modest protective effect (20% risk reduction) was suggested by the relative risk estimate, but the 95% confidence interval included the null value.

CONCLUSIONS

Motorcycle helmets were associated with a 69% reduction in skull fractures, 71% reduction in cerebral contusion, and 53% reduction in intracranial hemorrhage. This study finds that current motorcycle helmets do not protect equally against all types of head injury. Efforts to improve rotational acceleration management in motorcycle helmets should be considered.

Development and Prospective Validation of Tools to Accurately Identify Neurosurgical and Critical Care Events in Children With Traumatic Brain Injury

OBJECTIVE

To develop and validate case definitions (computable phenotypes) to accurately identify neurosurgical and critical care events in children with traumatic brain injury.

DESIGN

Prospective observational cohort study, May 2013 to September 2015.

SETTING

Two large U.S. children's hospitals with level 1 Pediatric Trauma Centers.

PATIENTS

One hundred seventy-four children less than 18 years old admitted to an ICU after traumatic brain injury.

MEASUREMENTS AND MAIN RESULTS

Prospective data were linked to database codes for each patient. The outcomes were prospectively identified acute traumatic brain injury, intracranial pressure monitor placement, craniotomy or craniectomy, vascular catheter placement, invasive mechanical ventilation, and new gastrostomy tube or tracheostomy placement. Candidate predictors were database codes present in administrative, billing, or trauma registry data. For each clinical event, we developed and validated penalized regression and Boolean classifiers (models to identify clinical events that take database codes as predictors). We externally validated the best model for each clinical event. The primary model performance measure was accuracy, the percent of test patients correctly classified. The cohort included 174 children who required ICU admission after traumatic brain injury. Simple Boolean classifiers were greater than or equal to 94% accurate for seven of nine clinical diagnoses and events. For central venous catheter placement, no classifier achieved 90% accuracy. Classifier accuracy was dependent on available data fields. Five of nine classifiers were acceptably accurate using only administrative data but three required trauma registry fields and two required billing data.

CONCLUSIONS

In children with traumatic brain injury, computable phenotypes based on simple Boolean classifiers were highly accurate for most neurosurgical and critical care diagnoses and events. The computable phenotypes we developed and validated can be used in any observational study of children with traumatic brain injury and can reasonably be applied in studies of these interventions in other patient populations.

Computed Tomography Use for Adults With Head Injury: Describing Likely Avoidable Emergency Department Imaging Based on the Canadian CT Head Rule

BACKGROUND

Millions of head computed tomography (CT) scans are ordered annually, but the extent of avoidable imaging is poorly defined.

OBJECTIVES

The objective was to determine the prevalence of likely avoidable CT imaging among adults evaluated for head injury in 14 community emergency departments (EDs) in Southern California.

METHODS

We conducted an electronic health record (EHR) database and chart review of adult ED trauma encounters receiving a head CT from 2008 to 2013. The primary outcome was discordance with the Canadian CT Head Rule (CCHR) high-risk criteria; the secondary outcome was use of a neurosurgical intervention in the discordant cohort. We queried systemwide EHRs to identify CCHR discordance using criteria identifiable in discrete data fields. Explicit chart review of a subset of discordant CTs provided estimates of misclassification bias and assessed the low-risk cases who actually received an intervention.

RESULTS

Among 27,240 adult trauma head CTs, EHR data classified 11,432 (42.0%) discordant with CCHR recommendation. Subsequent chart review showed that the designation of discordance based on the EHR was inaccurate in 12.2% (95% confidence interval [CI] = 5.6% to 18.8%). Inter-rater reliability for attributing CCHR concordance was 95% (κ = 0.86). Thus, we estimate that 36.8% of trauma head CTs were truly likely avoidable (95% CI = 34.1% to 39.6%). Among the likely avoidable CT group identified by EHR, only 0.1% (n = 13) received a neurosurgical intervention. Chart review showed none of these were actually "missed" by the CCHR, as all 13 were misclassified.

CONCLUSION

About one-third of head CTs currently performed on adults with head injury may be avoidable by applying the CCHR. Avoidance of CT in such patients is unlikely to miss any important injuries.

The International Incidence of Traumatic Brain Injury: A Systematic Review and Meta-Analysis

BACKGROUND

Understanding the epidemiology of traumatic brain injury (TBI) is essential to shape public health policy, implement prevention strategies, and justify allocation of resources toward research, education, and rehabilitation in TBI. There is not, to our knowledge, a systematic review of population-based studies addressing the epidemiology of TBI that includes all subtypes. We performed a comprehensive systematic review and meta-analysis of the worldwide incidence of TBI.

METHODS

A search was conducted on May 23, 2014, in Medline and EMBASE according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Abstracts were screened independently and in duplicate to identify original research. Study quality and ascertainment bias were assessed in duplicate using a previously published tool. Demographic data and incidence estimates from each study were recorded, along with stratification by age, gender, year of data collection, and severity.

RESULTS

The search strategy yielded 4944 citations. Two hundred and sixteen articles met criteria for full-text review; 144 were excluded. Hand searching resulted in ten additional articles. Eighty-two studies met all eligibility criteria. The pooled annual incidence proportion for all ages was 295 per 100,000 (95% confidence interval: 274-317). The pooled incidence rate for all ages was 349 (95% confidence interval: 96.2-1266) per 100,000 person-years. Incidence proportion and incidence rate were examined to see if associated with age, sex, country, or severity.

CONCLUSIONS

We conclude that most TBIs are mild and most TBIs occur in males among the adult population. The incidence of TBI varies widely by ages and between countries. Despite being an important medical, economic, and social problem, the global epidemiology of TBI is still not well-characterized in the current literature. Understanding the incidence of TBI, particularly mild TBI, remains challenging because of nonstandardized reporting among neuroepidemiological studies.