Response to Letter Regarding Article, “Predicting Clinical Outcomes After Thrombolysis Using the iScore: Results From the Virtual International Stroke Trials Archive”
Bibliographic record
Abstract
Trials Archive"We thank Drs Rangaraju and Jadhav for their interest and positive comments on our article.1 They suggest that a modified Rankin Scale of 0 to 3 at 3 months may be an acceptable outcome after tissue-type plasminogen activator (tPA) for patients with stroke with an expected poor prognosis (as identified by an iScore≥200).Drs Rangaraju and Jadhav offered some estimation for an acceptable outcome and death at 3 months in favor of tPA.However, it is important to recognize that these estimations are not adjusted for significant differences in baseline characteristics, for example, age, baseline National Institutes of Health Stroke Scale, and onset to treatment, between tPA and untreated patients as illustrated in the original publication and in the online-only Data Supplement. 1 As we showed, when applying the iScore to the Virtual International Stroke Trials Archive (VISTA) data set, there was a consistent benefit with tPA for patients with an expected good prognosis (iScore<200) across all outcome measures.1 However, no significant benefit with tPA was identified for patients with an iScore≥200 (which represented 10% of the entire cohort).In the VISTA cohort, we also found that tPA might decrease the risk of the composite catastrophic outcome-defined as severe disability or death (modified Rankin Scale, 4-6)-among patients with an iScore≥200.This could be because of the higher probability of reaching significance when a substantially larger number of patients achieve an outcome (ceiling effect).Consequently, it is difficult to be certain of the effect of tPA in this subgroup of patients (iScore≥200) with an expected poor outcome.Interestingly, previous studies applying the iScore to other data sets showed consistent results: patients with an iScore≥200 did not achieve better outcomes with tPA.2,3 For example, among patients with an iScore≥200 in the NINDS trials, tPA was not associated with a reduction in the risk of a catastrophic outcome (or regaining independency) at 3 months (tPA 70.7% versus placebo 76.9%; odds ratio, 0.73 [95% confidence interval, 0.31-1.68])or at 1 year (tPA 77.4 versus placebo 78.4; odds ratio, 0.94 [95% confidence interval, 0.39-2.31]).3 The risk of symptomatic intracerebral hemorrhage was >4.5× higher
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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 | 0.004 | 0.029 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.003 | 0.002 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.041 | 0.029 |
| Insufficient payload (model declined to judge) | 0.005 | 0.009 |
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".