Effect of dementia on 1‐year mortality in subdural hematoma: a preliminary analysis
Bibliographic record
Abstract
BACKGROUND: Aging and brain atrophy are risk factors for subdural hematoma (SDH). This preliminary analysis aims to quantify the effect of living with dementia on 1-year mortality following hospital admission for SDH. METHOD: Medical record data between Dec 2021 and Jan 2023 were reviewed retrospectively with a sampling rate of 1:2 (with dementia: without dementia) for participants with SDH managed conservatively. Propensity score matching (PSM) was used to estimate the average marginal effect of living with dementia on 1-year mortality, accounting for covariates (age, sex, chronicity of SDH, average hematoma width, midline shift). We used a 1:1 nearest neighbour PSM without replacement with propensity scores estimated using logistic regression of dementia status on covariates. Risk Ratio (RR) with 95% confidence intervals (CI) is reported from logistic regression after PSM to evaluate the association between dementia (as the sole predictor due to a low event rate <10) and 1-year mortality, with statistical significance considered at p < 0.05. RESULT: A total of 54 adults with a mean age of 77±15 were included, 50% (27/60) being men, 39% (21/54) having dementia, and 7.4% (4/54) having chronic SDH. The 1-year mortality rate was approximately twice in those living with dementia, 19% (4/21) vs. without 9.1% (3/33) (Cramer V = .14, df = 1, N = 54). After PSM, 12 non-dementia cases were excluded, and all covariate differences were 0.3, indicating an acceptable balance for preliminary analysis. The effect of dementia on 1-year mortality is as follows: RR = 1.33, 95% CI [0.28, 6.18], p = 0.713, N = 42. CONCLUSION: 1-year mortality appears 33% more likely in the dementia cohort, but the confidence interval is too wide to be conclusive. A sample size of 154 is needed for sufficient power (1-β=0.80, α=0.05) and to include covariates with an absolute std. mean difference of > 0.1 after PSM. Additional information: Funded by the Canadian Institutes of Health Research Micheal Smith Foreign Study Supplement (Funding reference number: FSS - 191081).
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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 | 0.008 | 0.015 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.008 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 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) | 0.006 | 0.001 |
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".