Table 1:
Description of Measures
| Construct | Summary of Measure | |
|---|---|---|
| NTDB Measures | ||
| Abbreviated Injury Scale (AIS)/Injury Severity Scale (ISS) | Head Injury Severity Non-Head Injury Severity |
⮚ An anatomical trauma severity scale that quantifies overall severity of injury across multiple body regions.57 ⮚ Injuries are ranked on a scale of 1 to 6, with 1 being minor, and 6 being an unsurvivable injury ⮚ ISS scores are derived from the AIS, calculated as the sum of the square of the three most severely injured body regions.58 ⮚ The most severe head injury was taken as max head AIS ⮚ Extra-cranial ISS was calculated as the sum of the square of the three most severely injured extracranial body regions |
| Glasgow Coma Scale (GCS) | Head Injury Severity | ⮚ Most commonly used tool of acute neurological injury severity ⮚ Focuses on verbal response, eye opening, and motor response59 ⮚ Scores range from 3–15, with 3 being most severe and 15 being most mild |
| Infectious Complications | Infectious Burden | ⮚ Coded based on presence of: deep wound infection, urinary tract infection, or pneumonia during acute hospital stay |
| Alcohol Blood Level | Alcohol use at time of injury | ⮚ Blood Alcohol Level was measured through blood draw at the acute facility and is expressed as a concentration of grams/dL. |
| Drug Use at Time of Injury | Drug use at time of injury | ⮚ Drug use at time of injury was determined with blood draw at the acute facility. |
| Mechanism of Injury | Intent | ⮚ Mechanism of Injury caused by: accident, assault, or self-inflicted |
| TBIMS Measures | ||
| Years of Education | Education | ⮚ Education level at the time of injury ⮚ Coded binary with high school education or greater, or less than high school level education |
| Race | Race | ⮚ Race was categorized as white, black, Asian, Native American, and other. |
| Payor Source | Health Care Resources | ⮚ Payor was dichotomized as Medicare and Medicaid vs. all others. |
| Functional Independence Measure (FIM) | Motor Disability Cognitive Disability |
⮚ The FIM is the most widely accepted and used measure of functional recovery during inpatient rehabilitation and following community integration60 ⮚ An 18-item ordinal scale assessing level of physical, motor, and cognitive disability ⮚ The cognitive and motor sub-scores at follow-up were used in this study |
| Patient Health Questionnaire-9 (PHQ-9) | Depressive Symptoms | ⮚ A 9-item ordinal screening questionnaire based on the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) criteria for Major Depressive Disorder ⮚ Has been validated for use in Traumatic Brain Injured populations61 ⮚ The PHQ8 Scoring (questions 1–8 only) was used in this study as a measure of depressive symptoms to predict suicidality |
| Time to Follow Commands (Days) | Injury Severity | ⮚ Refers to the date following injury that a patient is able to follow motor commands ⮚ The individual must either: follow simple motor commands accurately at least two out of two times within a 24 hour period, or have a score 6 on the motor component of the GCS |
| Substance Abuse at Time of Follow-up | Substance Abuse at follow-up | ⮚ Participant is asked the following question at the time of follow-up, “During the last 12 months, did you use any illicit or non-prescription drugs?” |
| Pre-injury Suicide Attempt | Pre-injury Suicide Attempt | ⮚ Participant is asked the following question at the time of enrollment into the study, “Have you ever attempted suicide?” |
| Outcome Measures | ||
| PHQ9 – Question #9 | Suicidal Ideation | ⮚ PHQ9 Question 9 assesses suicidal ideation and asks, over the last two weeks, how often have they been bothered by “Thoughts that you would be better off dead or of hurting yourself in some way”? ⮚ Use of single items from large depressive symptom inventories has been validated for assessing suicidal ideation.62 ⮚ Suicidal ideation was defined as a score of ≥1 and no suicide attempt in the past year |
| Suicidal Attempt in the past year | Suicide Attempt | ⮚ This was determined in follow up interview with either the participant or proxy. The question specified suicide attempt in the previous year. |