Restrictive versus liberal blood transfusion strategies in patients with myocardial infarction and anemia: individual patient data meta-analysis of randomized trials
Bibliographic record
Abstract
Abstract Background There are insufficient data to guide the appropriate use of red blood cell transfusion in patients with anemia and acute myocardial infarction (MI). Purpose To combine individual patient data from randomized clinical trials evaluating restrictive versus liberal transfusion strategies in patients with acute MI and anemia to generate precise estimates of treatment effects. Methods We searched all major databases to identify trials comparing restrictive versus liberal transfusion strategies in patients with acute MI and anemia (Hgb < 10 g/dl). We included studies that allocated participants to a liberal transfusion strategy that maintained hemoglobin greater than 10 g/dL or a restrictive transfusion strategy in which transfusion was administered if hemoglobin concentration was less than 8 g/dL. The primary outcome was a composite of 30-day death or MI. Secondary outcomes included 30-day death, 30-day cardiac death, and 6-month death. One-stage individual patient data meta-analyses were performed using a multilevel generalized linear model accounting for the clustering of patients within trials. Results We included 4311 participants from four trials. The primary outcome occurred in 334 patients (15.4%) in the restrictive and 296 patients (13.8%) in the liberal strategy (relative risk (RR) 1.13, 95% confidence interval (CI), 0.97 to 1.30) (figure 1). Death at 30-days occurred in 201 patients (9.3%) in the restrictive and 174 patients (8.1%) in the liberal strategy (RR 1.15; 95% CI, 0.95 to 1.39). Cardiac death at 30 days occurred in 5.5% in the restrictive strategy compared to 3.7% in the liberal strategy (RR 1.47; 95% CI, 1.11 to 1.94). Heart failure and thromboembolism occurred slightly more frequently in the liberal transfusion strategy group. Death at six months was higher in the restrictive (20.5%) compared to the liberal strategy (19.1%) (hazard ratio (HR) 1.08; 95% CI 1.05 to 1.11) (figure 2). The HR for cardiac death at 6 months was higher with a restrictive than liberal strategy (HR 1.38; 95% CI 1.08 to 1.76). In contrast, the HR for non-cardiac death at 6 months was lower with a restrictive than a liberal transfusion strategy (HR 0.89; 95% CI 0.84 to 0.94). Adjustment for baseline characteristics minimally changed the relative risk. Results for subgroups were similar except in patients without a history of renal failure whose risk of death or MI was increased with a restrictive strategy (RR 1.19; 95% CI, 1.01 to 1.39). Conclusions Pooled data from randomized trials found no significant differences for the primary outcome 30-day death or MI, but risk of cardiac death at 30 days and all cause death at 6 months was higher with a restrictive transfusion strategy. Given most outcomes favored liberal transfusion, and the risks from liberal transfusion were low, it may be prudent to use a liberal transfusion strategy in patients with acute MI and anemia.
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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 | 0.033 | 0.066 |
| Meta-epidemiology (narrow) | 0.004 | 0.002 |
| Meta-epidemiology (broad) | 0.024 | 0.048 |
| Bibliometrics | 0.005 | 0.005 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.003 | 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".