Intracranial hemorrhage after head injury among older patients on anticoagulation seen in the emergency department: a population-based cohort study
Bibliographic record
Abstract
BACKGROUND: Intracranial hemorrhage (ICH) after head injury is a concern among older adult patients on anticoagulation. We evaluated the risk of ICH after an emergency department visit for head injury among patients 65 years and older taking warfarin or a direct oral anticoagulant (DOAC) compared with patients not taking anticoagulants. We also evaluated risk of 30-day mortality and neurosurgical intervention among patients with ICH. METHODS: In this retrospective cohort study, we used population-based data of patients 65 years and older seen in an Ontario emergency department with a head injury. We matched patients on the propensity score to create 3 pairwise-matched cohorts based on anticoagulation status (warfarin v. DOAC, warfarin v. no anticoagulant, DOAC v. no anticoagulant). For each cohort, we calculated the relative risk of ICH at the index emergency department visit and 30-day mortality. We also calculated the hazard of neurosurgical intervention among patients with ICH. RESULTS: We identified 77 834 patients with head injury, including 64 917 (83.4%) who were not on anticoagulation, 9214 (11.8%) who were on DOACs and 3703 (4.8%) who were on warfarin. Of these, 5.9% of patients had ICH at the index emergency department visit. Patients on warfarin had an increased risk of ICH compared with matched patients on DOACs (relative risk [RR] 1.43, 95% confidence interval [CI] 1.20-1.69) and patients not on anticoagulation (RR 1.36, 95% CI 1.15-1.61). We did not observe a difference in ICH between patients on DOACs compared with matched patients not on anticoagulation. In patients with ICH, 30-day mortality did not differ by anticoagulation status or type. Patients on warfarin had an increased hazard of neurosurgery compared with patients not on anticoagulation. INTERPRETATION: Patients on warfarin seen in the emergency department with a head injury had higher relative risks of ICH than matched patients on a DOAC and patients not on anticoagulation, respectively. The risk of ICH for patients on a DOAC was not significantly different compared with no anticoagulation. Further research should confirm that older adults using warfarin are the only group at higher risk of ICH after head injury.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".