Table 1. Baseline Characteristics of Patients in a Study of the Effect of Tranexamic Acid vs Placebo on Neurologic Outcomes in Patients With Traumatic Brain Injury.
| Characteristic | Bolus maintenance (n = 312) | Bolus only (n = 345) | Placebo (n = 309) |
|---|---|---|---|
| Demographics | |||
| Age, median (IQR), y | 39 (26-57) | 40 (26-56) | 36 (25-55) |
| Sex, No. (%) | |||
| Female | 85 (27) | 90 (26) | 76 (25) |
| Male | 227 (73) | 255 (74) | 233 (75) |
| Race, No. (%)a | (n = 273) | (n = 295) | (n = 271) |
| American Indian/Alaska Native | 4 (1) | 4 (1) | 2 (1) |
| Asian | 13 (5) | 10 (3) | 7 (3) |
| Black/African American | 50 (18) | 53 (18) | 46 (17) |
| Native Hawaiian/other Pacific Islander | 1 | 1 | 1 |
| White | 202 (74) | 227 (77) | 213 (79) |
| More than 1 race | 3 (1) | 0 | 2 (1) |
| Ethnicitya | (n = 264) | (n = 294) | (n = 265) |
| Hispanic | 40 (15) | 43 (15) | 40 (15) |
| Injury characteristics | |||
| Injury type, No. (%)b | |||
| Blunt | 302 (97) | 339 (98) | 294 (95) |
| Penetrating (primarily gunshot wounds) | 12 (4) | 5 (1) | 16 (5) |
| Cause of injury | (n = 312) | (n = 340) | (n = 308) |
| Motor vehicle | |||
| Occupant | 103 (33) | 115 (34) | 113 (37) |
| Motorcycle | 32 (10) | 44 (13) | 33 (11) |
| Bicycle/pedestrian | 61 (20) | 62 (18) | 56 (18) |
| Fall at ground level | 44 (14) | 45 (13) | 37 (12) |
| Fall at more than 1 m | 40 (13) | 38 (11) | 32 (10) |
| Assault | 20 (6) | 25 (7) | 24 (8) |
| Suicide attempt | 8 (3) | 5 (1) | 9 (3) |
| Other | 4 (1) | 6 (2) | 4 (1) |
| Out-of-hospital Glasgow Coma Scale score, mean (SD)c | 7.8 (3.3) | 7.8 (3.3) | 7.6 (3.2) |
| Out-of-hospital Glasgow Coma Scale score, No. (%) | |||
| 3-4 | 72 (23) | 81 (23) | 69 (22) |
| 5-6 | 50 (16) | 52 (15) | 62 (20) |
| 7-8 | 47 (15) | 44 (13) | 55 (18) |
| 9-10 | 58 (19) | 77 (22) | 44 (14) |
| 11-12 | 71 (23) | 82 (24) | 71 (23) |
| 13-15 | 14 (4) | 9 (3) | 8 (3) |
| Maximum AIS head score, No. (%)d | (n = 306) | (n = 344) | (n = 301) |
| 0 (none) | 72 (24) | 84 (24) | 65 (22) |
| 1 (minor) | 14 (5) | 19 (6) | 11 (4) |
| 2 (moderate) | 48 (16) | 48 (14) | 46 (15) |
| 3 (serious) | 64 (21) | 66 (19) | 61 (20) |
| 4 (severe) | 56 (18) | 71 (21) | 67 (22) |
| 5 (critical) | 52 (17) | 55 (16) | 50 (17) |
| 6 (unsurvivable) | 0 | 1 | 1 |
| ISS, median (IQR)d | 17 (8-27) | 17 (8-27) | 17 (9-27) |
| Intracranial hemorrhage on initial computed tomographic imaging, No. (%)e | 177 (59) (n = 308) | 197 (58) (n = 339) | 171 (57) (n = 299) |
| Out-of-hospital care | |||
| Advanced airway, No. (%) | 161 (52) | 166 (48) | 168 (54) |
| Emergency medical services time, median (IQR), minf | 49 (36-66) | 47 (33-65) | 48 (35-63) |
| Air transport, No. (%) | 113 (36) | 124 (36) | 104 (34) |
| Out-of-hospital study drug infusion | |||
| Time from injury to start of infusion, median (IQR), ming | 43 (29-62) | 40 (29-65) | 41 (30-58) |
| Entire bolus infused, No. (%) | 285 (93) | 327 (95) | 290 (94) |
| No infusion-related deviations, No. (%)h | 297 (95) | 334 (97) | 304 (98) |
| In-hospital study drug infusion | |||
| Started, No. (%) | 254 (81) | 297 (86) | 244 (79) |
| Time to start of infusion, median (IQR), mini | 88 (60-130) | 94 (65-134) | 86 (60-120) |
| Entire bag infused, No. (%) | 229 (73) | 266 (77) | 214 (69) |
| No infusion-related deviations, No. (%)h | 295 (95) | 335 (97) | 294 (95) |
Abbreviation: IQR, interquartile range.
Race and ethnicity data were obtained through the medical record of participating sites. Study staff at the sites transcribed information from the medical record into fixed categories on the trial case report form. Race and ethnicity are not reported for the Canadian sites.
Four participants with penetrating mechanism also had blunt mechanism (2 in the bolus maintenance group, 1 in the bolus only group, and 1 in the placebo group). Two participants in the bolus only group were found to have no blunt or penetrating injury. All but 3 penetrating injuries were gunshot wounds (2 in the bolus maintenance group and 1 in the bolus only group). Penetrating injury differs between groups (χ2 P value = .03).
The Glasgow Coma Scale (GCS) score is a neurologic scale that ranges from 3 to 15, with lower scores indicating a lower level of consciousness. The overall score is the sum of 3 components. The eye response ranges from 1 (no opening) to 4 (eyes opening spontaneously), the verbal response from 1 (no response) to 5 (oriented), and the motor response from 1 (no motor response) to 6 (obeys commands). GCS scores of 8 or lower generally indicate severe brain injury; 9 to 12, moderate brain injury; and 13 to 15, minor brain injury.
In injury severity scoring, each injury is assigned an Abbreviated Injury Scale (AIS) score that ranges from 1 (minor) to 6 (unsurvivable). Each of 6 regions (head/neck, face, chest, abdomen, extremity, external) is assigned a regional score by taking the highest AIS score in the region. The Injury Severity Score (ISS) is the sum of the squares of each of the 3 highest regional scores. The ISS ranges from 0 to 75, with higher scores indicating greater severity of injury. Patients with injury with an AIS score of 6 in any region are automatically assigned the highest ISS of 75. An ISS greater than 15 is generally considered major trauma. ISS was missing for 18 patients (8 in the bolus maintenance group, 3 in the bolus only group, and 7 in the placebo group).
Participants who died before receiving a head scan and for whom there was no other evidence of intracranial bleeding and patients with “indeterminate” head computed tomographic imaging findings for intracranial bleeding by the central reader are excluded (eTable 12 in Supplement 2). This indicator is not a baseline measure but is included here because it is used for a subgroup definition.
Time from call to dispatch to arrival at the emergency department.
Time of injury was estimated by emergency medical service personnel. If there was no basis to estimate the time, personnel were instructed not to enroll because inclusion criteria included enrolling within 2 hours of injury.
No protocol deviations or violations related to infusion. Eligibility status is not considered a deviation for this measure.
Time from completion of out-of-hospital infusion to start of in-hospital infusion.