Mazer 2017.
| Study characteristics | ||
| Methods |
Design: RCT, parallel 2‐arm, multicentre, open‐label, non‐inferiority trial Setting: 73 sites in 19 countries (Australia, Brazil, Canada, China, Colombia, Denmark, Egypt, Germany, Greece, India, Israel, Malaysia, New Zealand, Romania, Singapore, South Africa, Spain, Switzerland, USA) Recruitment: January 2014 to March 2017 Maximum follow‐up: 28 days |
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| Participants | People 18 years of age or older who were scheduled to undergo cardiac surgery with CPB and who had a preoperative EuroSCORE I ≥ 6 5035 participants were randomised in the main trial; 208 had been randomised in the multicentre pilot trial 5092 participants were used in modified ITT analyses; numbers below are as for per‐protocol analysis
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| Interventions |
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| Outcomes |
Primary outcome: a composite of death from any cause, non‐fatal myocardial infarction, stroke, or new‐onset renal failure with dialysis, occurring during the index hospitalisation from the start of surgery until either hospital discharge or 28 days after surgery, whichever occurred first Secondary outcomes included: components of the primary outcome, blood‐product (including red‐cell) transfusion, lengths of stay in the ICU and in the hospital, duration of mechanical ventilation, prolonged state of low cardiac output, infection, bowel infarction, acute kidney injury, seizure, delirium, encephalopathy |
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| Notes | Primary results were presented per protocol rather than by intention to treat. This prespecified analysis included all participants except those who had protocol adherence < 90%, those who were withdrawn from the trial by the treating physician at any time, and those who withdrew consent Trial title: The Transfusion Requirements in Cardiac Surgery ‐ TRICS III Trial registration: NCT02042898 Trial funding: supported by grants (232416 and 301852) from the Canadian Institutes of Health Research, by a grant (Kenneth J. Fyke Award, to Dr. Shehata) from the Canadian Blood Services – Health Canada, by a grant (1085942) from the National Health and Medical Research Council of Australia, and by a grant (16/353) from the Health Research Council of New Zealand COI statement by investigators: on file in supplementary forms at https://www.nejm.org/doi/suppl/10.1056/NEJMoa1711818/suppl_file/nejmoa1711818_disclosures.pdf |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "Computer generated random permuted blocks randomly assigned to one of two red‐cell transfusion strategies, in a 1:1 ratio with the use of a concealed centralized, Web‐based system, stratified according to center, with computer‐generated random permuted blocks of varying sizes from two to six" (Mazer 2017 p 2) |
| Allocation concealment (selection bias) | Low risk | Concealed centralised web‐based system (as above) |
| Blinding of participants and personnel (performance bias) Objective outcomes | Low risk | Blinding of personnel for this intervention is not feasible, but in our view, for objective outcomes such as mortality (the primary outcome used within this review), we graded risk of bias as 'low' Patients and clinical teams were not blinded |
| Blinding of outcome assessment (detection bias) Objective measures | Low risk | Blinding of mortality (the primary outcome used within this review) is not relevant, and we graded risk of bias as 'low' Outcomes were adjudicated by committee blinded to treatment assignment |
| Blinding of outcome assessment (detection bias) Subjective measures | Low risk | No data from subjective outcomes (e.g. function) |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Not apparent. Losses to follow‐up low (5092 from 5243 patients) |
| Selective reporting (reporting bias) | Low risk | Trial was prospectively registered (NCT02042898). No evidence of selective reporting |
| Other bias | Low risk | None evident |