Summary of findings 1. Liberal compared with restrictive transfusion protocols for guiding red blood cell transfusion.
| Liberal compared with restrictive transfusion protocols for guiding red blood cell transfusion | ||||||
| Patient or population: adults and children (haemodynamically stable) with potential need for RBC transfusion Setting: inpatients Intervention: restrictive transfusion threshold Comparison: liberal transfusion threshold | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | №. of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with liberal transfusion protocol | Risk with restrictive transfusion protocol | |||||
| Participants exposed to blood transfusion (all studies) | Study population | RR 0.59 (0.53 to 0.66) | 20,057 (42) | ⊕⊕⊕⊕ High | ||
| 815 per 1000 | 481 per 1000 (432 to 538) | |||||
| 30‐Day mortality | Study population | RR 0.99 (0.86 to 1.15) | 16,729 (31) | ⊕⊕⊕⊕ High | ||
| 83 per 1000 | 83 per 1000 (71 to 96) | |||||
| Myocardial infarction | Study population | RR 1.04 (0.87 to 1.24) | 14,370 (23) | ⊕⊕⊕⊕ High | ||
| 32 per 1000 | 33 per 1000 (28 to 40) | |||||
| Congestive heart failure | Study population | RR 0.83 (0.53 to 1.29) | 7247 (16) | ⊕⊕⊝⊝ Lowa | ||
| 35 per 1000 | 29 per 1000 (19 to 45) | |||||
| Cerebrovascular accident ‐ stroke | Study population | RR 0.84 (0.64 to 1.09) | 13,985 (19) | ⊕⊕⊕⊕ High | ||
| 17 per 1000 | 14 per 1000 (11 to 19) | |||||
| Rebleeding | Study population | RR 0.80 (0.59 to 1.09) | 3412 (8) | ⊕⊕⊕⊝ Moderateb | ||
| 158 per 1000 | 126 per 1000 (93 to 172) | |||||
| Thromboembolism | Study population | OR 1.11 (0.65 to 1.88) | 4201 (13) | ⊕⊕⊕⊝ Moderatec | ||
| 15 per 1000 | 17 per 1000 (10 to 28) | |||||
| Infection | Study population | RR 0.97 (0.88 to 1.07) | 17,104 (25) | ⊕⊕⊕⊕ High | ||
| 143 per 1000 | 139 per 1000 (126 to 153) | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; OR: odds ratio; RBC: red blood cell; RR: risk ratio | ||||||
| GRADE Working Group grades of evidence. High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. | ||||||
aWe downgraded once for inconsistency, as there was no consistency in the direction of the effect (despite the relatively low statistical heterogeneity), and we downgraded once for imprecision, as there were very low numbers of events.
bDespite relatively low statistical heterogeneity, there was no consistency in the direction of the effect, hence we downgraded once for inconsistency.
cDowngraded once for imprecision, as there were few events (and hence a wide CI).