Effect of four hemoglobin transfusion threshold strategies in patients with acute myocardial infarction and anemia: a target trial emulation using MINT trial data
Bibliographic record
Abstract
Abstract Background The hemoglobin (Hgb) threshold at which red blood cell transfusion affords greatest benefit, without increasing transfusion-associated risks, is uncertain for patients with acute myocardial infarction (MI). The Myocardial Ischemia and Transfusion (MINT) trial recently showed a restrictive transfusion strategy (Hgb threshold <7-8g/dL) resulted in a 15% increased risk of 30-day all-cause death or recurrent MI (death/MI) compared with a liberal strategy (Hgb threshold <10g/dL) in 3,504 adults with acute MI and anemia. However, the transfusion effect at different Hgb thresholds remains uncertain. Purpose To better understand the gradient of effects from Hgb threshold transfusion triggers between 7g/dL and 10g/dL. We estimated the effects of four Hgb transfusion thresholds on 30-day death/MI and death in patients with acute MI and anemia. Methods We used data from the MINT trial and applied an innovative causal inference method, target trial emulation, to assess four Hgb thresholds. We emulated a hypothetical, 4-arm target trial of <10g/dL, <9g/dL, <8g/dL, and <7g/dL transfusion strategies in adults with acute MI and Hgb <10g/dL using a "cloning" procedure. The target trial protocol closely mirrored that of the MINT trial. We conducted a per-protocol analysis of the emulated target trial using censoring and inverse probability (IP) weighting; we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) by fitting pooled logistic regression models with a time-dependent intercept for time free of the outcomes. We estimated IP weighted Kaplan-Meier cumulative incidence curves under each strategy for 30-day outcomes. Results Of the MINT trial participants, 3,492 (99.7%) met eligibility criteria for the hypothetical target trial of four transfusion strategies. The unadjusted rate of 30-day death/MI was lowest in the <10g/dL strategy and highest in the <9g/dL strategy, and the rate of transfusions decreased monotonically as Hgb thresholds decreased. Relative to the <10g/dL strategy, the estimated HRs (95% CI) from the IP weighted model of 30-day death/MI were 1.07 (0.77-1.50) for the <9g/dL strategy, 1.14 (0.84-1.55) for the <8g/dL strategy, and 1.44 (0.99-2.09) for the <7g/dL strategy (Figure). A log-linear estimate over strategy thresholds between 7-10g/dL estimated a 1.12 (95% CI 1.00-1.27) times greater average risk of death/MI and a 1.12 (95% CI 0.92, 1.37) times greater average risk of death over 30 days for each 1g/dL decrease in the Hgb threshold. The IP weighted cumulative incidence curves showed similar increase in risk of death/MI as transfusion thresholds decreased throughout 30 days post-randomization. Conclusions Relative to a <10g/dL transfusion strategy, we estimated a progressively greater risk of 30-day death/MI as transfusion Hgb thresholds decreased within the range of 7-10g/dL. Targeting a Hgb concentration of 10g/dL in patients with a recent acute MI may avoid serious risks associated with anemia.Hazard ratios for 30-day death/MI
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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 | 0.111 | 0.154 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.011 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.002 | 0.004 |
| Insufficient payload (model declined to judge) | 0.005 | 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".