Abstract 35: Unmet Need In Acute Ischemic Stroke Patients Arriving After 4.5 Hours
Bibliographic record
Abstract
Introduction: Many patients arrive beyond the guideline-recommended time window for treatment with IV alteplase. For most of these patients, few treatment options exist. There is a need to understand the characteristics, outcomes, and healthcare costs of patients in this population in order to develop new treatments options. Methods: We analyzed patients ≥65 years old with a primary diagnosis of AIS arriving within 24 hours of time last known well (LKW) but not treated with IV alteplase at Get With The Guidelines-Stroke Hospitals in the United States (Jan 2016 - Dec 2016). We report clinical characteristics, 90-day and 1-year outcomes including Medicare costs, stratified by time from LKW to arrival (≤4.5 hours, >4.5-6 hours and >6-24 hours). Results: Of 39,760 patients (80.0% White, 10.5% Black, 4.1% Hispanic, 2.2% Asian), 20,369 (51.2%) presented from 4.5 - 24 hours of LKW. Compared to patients arriving within ≤4.5 hours, patients arriving within 4.5 - 24 hours of LKW were more likely to be Black, Hispanic, or Asian (≤4.5 hours: 9.4% Black, 3.8% Hispanic, 1.9% Asian; >4.5 - 6 hours: 11.7% Black, 4.1% Hispanic, 2.4% Asian; >6 - 24 hours since LKW: 11.6% Black, 4.4% Hispanic, 2.6% Asian; p < 0.001). The most common discharge location for those arriving within ≤4.5 hours was home; for those arriving >4.5 hours since LKW the most common discharge location was inpatient rehab (IRF) or skilled nursing facility (SNF) (≤4.5 hours: 44.7% home vs 42.3% IRF or SNF; >4.5 - 6 hours: 35.4% home vs 51.7% IRF or SNF; >6 - 24 hours: 35.8% home vs 51.0% IRF or SNF). The 90-day and 1-year mortality rates were 18.9% and 30.0% in those arriving within ≤4.5 hours, 19.0% and 29.8% in those arriving between 4.5 - 6 hours, and 19.1% and 29.1% in those arriving between 6 - 24 hours. Median 90-day inpatient costs were highest among those arriving 6 - 24 hours from LKW (≤4.5 hours: $9,471 [IQR: 5,622-21,356]; >4.5 - 6 hours: $10,884 [IQR: 6,036-25,992]; 6 -24 hours: $11,162 [6,073-26,372]). Conclusions: Results show the importance of timely hospital arrival, as well as a need to address racial disparities in arrival times, reduce costs, and develop new treatment options for patients with AIS arriving after 4.5 hours from last known well time.
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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 | 0.000 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| 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) | 0.017 | 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".