Vitamin A supplementation for preventing morbidity and mortality in very low birthweight infants

Abstract

Vitamin A is necessary for normal lung growth and the ongoing integrity of respiratory tract epithelial cells. Preterm infants have low vitamin A status at birth and this has been associated with increased risk of developing chronic lung disease. Several studies have been undertaken to assess whether vitamin A supplementation beyond that routinely given in multivitamin preparations can reduce the incidence of this outcome. To assess the benefit of supplementation with vitamin A in very low birthweight infants. Searches were made of the Oxford Database of Perinatal Trials, MEDLINE, Cochrane Controlled Trials Register, and Science Citation Index. The reference lists of relevant trials, recent issues of paediatric and nutrition journals, abstracts and proceedings from relevant conferences in the English language were hand searched. Randomised controlled trials which compared the effects of supplemental vitamin A with standard vitamin A regimes in infants with birthweight </=1500g, and which reported clinical outcomes (death, chronic lung disease or bronchopulmonary dysplasia) and/or vitamin A concentrations were considered for the review. Data on mortality, requirement for supplemental oxygen at one month of age and at 36 weeks post-menstrual age, retinopathy of prematurity and nosocomial sepsis were excerpted by both reviewers independently. Data analysis was conducted according to the standards of the Cochrane Neonatal Review Group. Six eligible trials were identified, one having a much larger sample size than the others combined. The meta-analysis suggests supplementation with vitamin A results in benefit in terms of reducing oxygen requirement at 36 weeks post-menstrual age [summary RR 0.85 (0.73, 0.98), RD -8.5% (-15.9, -1.1), NNT 11.8 (6.3, 90.9)] and trends towards reduction in death or oxygen requirement at 36 weeks post-menstrual age [summary RR 0.89 (0.79, 1.00)], oxygen use in survivors at one month of age [summary RR 0.93 (0.86, 1.01)], and death or oxygen requirement at one month of age [summary RR 0.93 (0. 86, 1.00)]. Meta-analysis of the two studies which reported on retinopathy of prematurity suggests a trend towards reduced incidence in vitamin A supplemented infants. Supplementing very low birthweight infants with vitamin A is associated with a reduction in oxygen requirement amongst survivors at 36 weeks post-menstrual age. Whether clinicians decide to utilise repeat intramuscular doses of vitamin A to prevent chronic lung disease may depend upon the local incidence of this outcome and the value attached to achieving a modest reduction in this outcome, balanced against the lack of other proven benefits and the acceptability of treatment. The benefits, in terms of vitamin A status, safety and acceptability of delivering vitamin A in an intravenous emulsion compared with repeat intramuscular injections should be assessed in a further trial.