Risk of bias in individual studies: Studies were classified by consensual agreement of two authors (CC and PZ) as having a low risk of bias, an unclear risk of bias, or a high risk of bias, on the Cochrane tool.16 The Cochrane tool takes into account random sequence generation, concealment of the allocation sequence, blinding of participants and study personnel, blinding of outcome assessment, incomplete outcome data, and selective reporting. Summary measures: Data concerning the primary continuous outcome, perioperative blood loss, were pooled using the ratio of the means method.17 Data concerning the binary outcome, transfusion of at least 1 unit of allogeneic red blood cells, were pooled using the Mantel-Haenszel odds ratio method without corrections.18 Planned methods of analysis: In trials with more than two intervention groups, it was planned to combine results for groups that received similar but non-identical interventions (as long as the group fulfilled the criteria for eligibility, as defined above) and it was planned not to include an intervention group if it did not match our inclusion criteria. Heterogeneity was explored by visual inspection of the forest plot, calculation of the Cochran Q heterogeneity statistic and calculation of the I2 statistic. A fixed-effect model was planned in the absence of heterogeneity, defined by a p value > 0.10 for the Cochran Q heterogeneity statistic and an I2 value < 25%. The model approach is also presented. Risk of bias across studies: The risk of publication bias was checked using the funnel plot technique for the primary outcome. Additional analyses: A sensitivity analysis was performed by restricting the meta-analysis to studies considered at low risk of bias (data not shown).
Risk of bias in individual studies: Studies were classified by consensual agreement of two authors (CC and PZ) as having a low risk of bias, an unclear risk of bias, or a high risk of bias, on the Cochrane tool.16 The Cochrane tool takes into account random sequence generation, concealment of the allocation sequence, blinding of participants and study personnel, blinding of outcome assessment, incomplete outcome data, and selective reporting. Summary measures: Data concerning the primary continuous outcome, perioperative blood loss, were pooled using the ratio of the means method.17 Data concerning the binary outcome, transfusion of at least 1 unit of allogeneic red blood cells, were pooled using the Mantel-Haenszel odds ratio method without corrections.18 Planned methods of analysis: In trials with more than two intervention groups, it was planned to combine results for groups that received similar but non-identical interventions (as long as the group fulfilled the criteria for eligibility, as defined above) and it was planned not to include an intervention group if it did not match our inclusion criteria. Heterogeneity was explored by visual inspection of the forest plot, calculation of the Cochran Q heterogeneity statistic and calculation of the I2 statistic. A fixed-effect model was planned in the absence of heterogeneity, defined by a p value > 0.10 for the Cochran Q heterogeneity statistic and an I2 value < 25%. The model approach is also presented. Risk of bias across studies: The risk of publication bias was checked using the funnel plot technique for the primary outcome. Additional analyses: A sensitivity analysis was performed by restricting the meta-analysis to studies considered at low risk of bias (data not shown).
ALN_127_3_2017_06_15_ZUFFERY_ALN-D-17-00118R3_SDC1.docx