Vitamin A supplementation in very-preterm or very-low-birth-weight infants to prevent morbidity and mortality: A systematic review and meta-Analysis of randomized trials

Background: A previous systematic review showed that intramuscular vitamin A supplementation reduced the risk of bronchopulmonary dysplasia (BPD) in very-low-birth-weight (VLBW) infants. However, more recent studies have questioned this finding. Objectives: Our objective was to synthesize current evidence on vitamin A supplementation in very-preterm (<32 wk gestational age) or VLBW infants and investigate the factors that may modify its efficacy. Methods: A systematic review was conducted using the Cochrane systematic review methodology. We included randomized controlled trials investigating vitamin A supplementation for reducing morbidity and mortality in very-preterm or VLBW infants. Certainty of evidence was assessed using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) recommendations. Prespecified subgroup analyses assessed factors that may modify the effects of vitamin A supplementation. Results: We included 17 studies (n = 2471) in the qualitative and 15 studies (n = 2248) in the quantitative synthesis. Moderate-certainty evidence suggested a beneficial effect of vitamin A for decreasing the risk of BPD at 36 wk postmenstrual age (RR: 0.83; 95% CI: 0.74, 0.93; numbers needed to treat for an additional beneficial outcome: 16; 95% CI: 9, 53; 9 studies, n = 1752; P = 0.002). Subgroup analysis suggested that the beneficial effect was limited to infants with baseline vitamin A intake <1500 IU · kg-1 · d-1. Both enteral and parenteral routes were effective. Vitamin A supplementation did not have adverse effects and did not alter mortality before discharge (12 studies, n = 1917) or neurodevelopmental outcomes at 18-22 mo (1 study, n = 538). Conclusions: The benefit of vitamin A supplementation for reducing BPD is likely to be limited to infants with baseline vitamin A intake <1500 IU · kg-1 · d-1 and is not affected by the route of administration.