Comparison 1. Superoxide dismutase versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 BPD defined as an oxygen requirement at 28 days	1	302	Risk Ratio (M‐H, Fixed, 95% CI)	1.09 [0.94, 1.26]
1.2 BPD defined as oxygen at 36 weeks' postmenstrual age	2	335	Risk Ratio (M‐H, Fixed, 95% CI)	0.96 [0.72, 1.29]
1.3 Neonatal Mortality	2	335	Risk Ratio (M‐H, Fixed, 95% CI)	0.98 [0.57, 1.68]
1.4 Mortality prior to discharge	2	78	Risk Ratio (M‐H, Fixed, 95% CI)	1.20 [0.53, 2.71]
1.5 Hemodynamically significant patent ductus arteriosus	1	33	Risk Ratio (M‐H, Fixed, 95% CI)	1.00 [0.45, 2.21]
1.6 Late onset sepsis (with proven culture)	2	335	Risk Ratio (M‐H, Fixed, 95% CI)	1.06 [0.78, 1.43]
1.7 Necrotizing enterocolitis	2	335	Risk Ratio (M‐H, Fixed, 95% CI)	0.80 [0.34, 1.84]
1.8 Intraventricular hemorrhage (any grade)	2	335	Risk Ratio (M‐H, Fixed, 95% CI)	0.98 [0.65, 1.47]
1.9 Severe Intraventricular hemorrhage (Grades III / IV)	2	335	Risk Ratio (M‐H, Fixed, 95% CI)	0.71 [0.39, 1.31]
1.10 Periventricular leukomalacia (PVL)	1	302	Risk Ratio (M‐H, Fixed, 95% CI)	0.64 [0.11, 3.78]
1.11 Retinopathy of prematurity (any stage)	2	277	Risk Ratio (M‐H, Fixed, 95% CI)	0.95 [0.78, 1.15]
1.12 Severe retinopathy of prematurity (stage II or greater)	1	244	Risk Ratio (M‐H, Fixed, 95% CI)	0.97 [0.57, 1.65]