Comparison 1. Red blood cell transfusions vs standard care.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Proportion of participants developing new or progressive SCI lesions	2		Risk Ratio (IV, Random, 95% CI)	Totals not selected
1.1 Normal TCD velocities	1		Risk Ratio (IV, Random, 95% CI)	0.0 [0.0, 0.0]
1.2 Abnormal TCD velocities	1		Risk Ratio (IV, Random, 95% CI)	0.0 [0.0, 0.0]
2 SCD ‐ related serious adverse events ‐ acute chest syndrome	2	326	Risk Ratio (IV, Random, 95% CI)	0.24 [0.12, 0.49]
2.1 Normal TCD velocities	1	196	Risk Ratio (IV, Random, 95% CI)	0.20 [0.08, 0.51]
2.2 Abnormal TCD velocities	1	130	Risk Ratio (IV, Random, 95% CI)	0.30 [0.11, 0.87]
3 SCD‐related serious adverse events ‐ pain crisis	2	326	Risk Ratio (IV, Random, 95% CI)	0.63 [0.42, 0.95]
3.1 Normal TCD velocities	1	196	Risk Ratio (IV, Random, 95% CI)	0.56 [0.40, 0.78]
3.2 Abnormal TCD velocities	1	130	Risk Ratio (IV, Random, 95% CI)	0.90 [0.44, 1.86]
4 Clinical stroke	2	326	Risk Ratio (IV, Random, 95% CI)	0.12 [0.03, 0.49]
4.1 Normal TCD velocities	1	196	Risk Ratio (IV, Random, 95% CI)	0.14 [0.02, 1.12]
4.2 Abnormal TCD velocities	1	130	Risk Ratio (IV, Random, 95% CI)	0.10 [0.01, 0.73]
5 Any transfusion‐related adverse events ‐ antibody development	1		Risk Ratio (IV, Random, 95% CI)	Totals not selected
5.1 Normal TCD velocities	1		Risk Ratio (IV, Random, 95% CI)	0.0 [0.0, 0.0]
6 Any transfusion‐related adverse events ‐ transfusion reactions	1		Risk Ratio (IV, Random, 95% CI)	Totals not selected
6.1 Normal TCD velocities	1		Risk Ratio (IV, Random, 95% CI)	0.0 [0.0, 0.0]