Summary of findings 1. Superoxide dismutase (SOD) compared to placebo for preventing bronchopulmonary dysplasia (BPD) in preterm infants.
| Superoxide dismutase (SOD) compared to placebo for preventing bronchopulmonary dysplasia (BPD) in preterm infants | ||||||
| Patient or population: preterm infants at risk of developing BPD Setting: neonatal intensive care units Intervention: SOD Comparison: placebo | ||||||
| Outcomes | Relative effect (95% CI) | Anticipated absolute effects* (95% CI) | Certainty of the evidence (GRADE) | What happens | ||
| Without SOD | With SOD | Difference | ||||
| BPD defined as an oxygen requirement at 28 days № of participants: 302 (1 RCT) | RR 1.09 (0.94 to 1.26) | Study population | ⊕⊝⊝⊝ Very low 1 | The evidence is very uncertain about the effect of superoxide dismutase on BPD defined as an oxygen requirement at 28 days compared to placebo. | ||
| 66.9% | 72.9% (62.9 to 84.3) | 6.0% more (4 fewer to 17.4 more) | ||||
| BPD defined as oxygen at 36 weeks' postmenstrual age № of participants: 335 (2 RCTs) | RR 0.96 (0.72 to 1.29) | Study population | ⊕⊝⊝⊝ Very low 1 | The evidence is very uncertain about the effect of superoxide dismutase on BPD defined as an oxygen at 36 weeks' postmenstrual age compared to placebo. | ||
| 35.2% | 33.8% (25.4 to 45.4) | 1.4% fewer (9.9 fewer to 10.2 more) | ||||
| Neonatal mortality (i.e. within 28 days) № of participants: 335 (2 RCTs) | RR 0.98 (0.57 to 1.68) | Study population | ⊕⊝⊝⊝ Very low 1 | The evidence is very uncertain about the effect of superoxide dismutase on neonatal mortality compared to placebo. | ||
| 13.8% | 13.6% (7.9 to 23.2) | 0.3% fewer (5.9 fewer to 9.4 more) | ||||
| Mortality prior to discharge № of participants: 78 (2 RCTs) | RR 1.20 (0.53 to 2.71) | Study population | ⊕⊝⊝⊝ Very low 1 | The evidence is very uncertain about the effect of superoxide dismutase on mortality prior to discharge compared to placebo. | ||
| 22.9% | 27.4% (12.1 to 61.9) | 4.6% more (10.7 fewer to 39.1 more) | ||||
| BPD or death at 36 weeks' postmenstrual age № of participants: 0 (0 RCTs) | Not reported | ‐ | ‐ | ‐ | ‐ | No studies reported this outcome. |
| Need for supplemental oxygen (days) № of participants: 0 (0 RCTs) | Not reported | ‐ | ‐ | ‐ | ‐ | No studies reported this outcome. |
| Retinopathy of prematurity № of participants: 277 (2 RCTs) | RR 0.95 (0.78 to 1.15) | Study population | ⊕⊝⊝⊝ Very low 1 | The evidence is very uncertain about the effect of superoxide dismutase on retinopathy of prematurity (any stage) compared to placebo. | ||
| 61.1% | 58.0% (47.6 to 70.2) | 3.1% fewer (13.4 fewer to 9.2 more) | ||||
| Severe retinopathy of prematurity (stage II or greater) № of participants: 244 (1 RCT) | RR 0.97 (0.57 to 1.65) | Study population | ⊕⊝⊝⊝ Very low 1 | The evidence is very uncertain about the effect of superoxide dismutase on severe retinopathy of prematurity (stage II or greater) compared to placebo. | ||
| 18.3% | 17.7% (10.1 to 29.3) | 0.6% fewer (8.2 fewer to 11 more) | ||||
| Moderate to severe neurodevelopmental outcome at 18 to 24 months № of participants: 0 (0 RCTs) | Not reported | ‐ | ‐ | ‐ | ‐ | No studies reported this outcome. |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; OR: odds ratio; RCT: randomized controlled trial; RR: risk ratio | ||||||
| GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. | ||||||
1 downgrade one level for risk of bias: unclear risk in multiple domains; downgrade two levels for imprecision: few events, small sample size, confidence interval overlapping the no difference line