Comparison 5. Iron supplementation: ferrous sulphate versus ferrous fumarate.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Deferral due to low haemoglobin (primary outcome)	1		Risk Ratio (M‐H, Random, 95% CI)	Totals not selected
1.1 Deferral after multiple donation visits	1		Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
2 Haemoglobin (g/L)	2		Mean Difference (IV, Random, 95% CI)	Totals not selected
2.1 Before further donation	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
2.2 After subsequent donation(s)	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
3 Serum or plasma iron (μg/dL)	2		Mean Difference (IV, Random, 95% CI)	Totals not selected
3.1 Before further donation	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
3.2 After subsequent donation(s)	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
4 Total iron binding concentration (μg/dL)	2		Mean Difference (IV, Random, 95% CI)	Totals not selected
4.1 Before further donation	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
4.2 After subsequent donation(s)	1		Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
5 Adverse effects	2		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
5.1 Cumulative adverse effects	1	433	Risk Ratio (M‐H, Random, 95% CI)	1.40 [1.04, 1.88]
5.2 Constipation	1	433	Risk Ratio (M‐H, Random, 95% CI)	1.46 [0.78, 2.72]
5.3 Diarrhoea	2	497	Risk Ratio (M‐H, Random, 95% CI)	0.70 [0.36, 1.35]
5.4 Nausea/vomiting	1	64	Risk Ratio (M‐H, Random, 95% CI)	0.33 [0.04, 3.04]
5.5 Abdominal pain and/or cramps	2	497	Risk Ratio (M‐H, Random, 95% CI)	0.58 [0.05, 6.53]