New clinical decision rule to exclude subarachnoid haemorrhage for acute headache: a prospective multicentre observational study
Bibliographic record
Abstract
OBJECTIVE: To ensure good outcomes in the management of subarachnoid haemorrhage (SAH), accurate prediction is crucial for initial assessment of patients presenting with acute headache. We conducted this study to develop a new clinical decision rule using only objectively measurable predictors to exclude SAH, offering higher specificity than the previous Ottawa SAH Rule while maintaining comparable sensitivity. DESIGN: Multicentre prospective cohort study. SETTING: Tertiary-care emergency departments of five general hospitals in Japan from April 2011 to March 2014. PARTICIPANTS: Eligible patients comprised 1781 patients aged >15 years with acute headache, excluding trauma or toxic causes and patients who presented in an unconscious state. MAIN OUTCOME MEASURES: Definitive diagnosis of SAH was based on confirmation of SAH on head CT or lumbar puncture findings of non-traumatic red blood cells or xanthochromia. RESULTS: A total of 1561 patients were enrolled in this study, of whom 277 showed SAH. Using these enrolled patients, we reached a rule with mainly categorical predictors used in previous reports, called the 'Ottawa-like rule', offering 100% sensitivity when using any of age ≥40 years, neck pain or stiffness, altered level of consciousness or onset during exertion. Using the 1317 patients from whom blood samples were obtained, a new rule using any of systolic blood pressure >150 mm Hg, diastolic blood pressure >90 mm Hg, blood sugar >115 mg/dL or serum potassium <3.9 mEq/L offered 100% sensitivity (95% CI 98.6% to 100%) and 14.5% specificity (12.5% to 16.9%), while the Ottawa-like rule showed the same sensitivity with a lower specificity of 8.8% (7.2% to 10.7%). CONCLUSIONS: While maintaining equal sensitivity, our new rule seemed to offer higher specificity than the previous rules proposed by the Ottawa group. Despite the need for blood sampling, this method can reduce unnecessary head CT in patients with acute headache. TRIAL REGISTRATION NUMBER: UMIN 00004871.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.007 | 0.024 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| 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".