Cromolyn sodium for the prevention of chronic lung disease in preterm infants

Background: Chronic lung disease (CLD) frequently occurs in preterm infants and has a multifactorial aetiology including inflammation. Cromolyn sodium is a mast cell stabiliser that inhibits neutrophil activation and neutrophil chemotaxis and may, therefore, have a role in the prevention of CLD.

Objectives: To determine the effect of prophylactic administration of cromolyn sodium on the incidence of CLD, mortality or the combined outcome of mortality or CLD at 28 days of life in preterm infants at risk of CLD.

Search methods: The search strategy of the Cochrane Neonatal Review Group was used to identify studies. Searches were made of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2009), MEDLINE, EMBASE, CINAHL up to and including July 2009, personal files and reference lists of identified trials. For this update the same data Bases were searched on 12 April 2012. In addition, on the same date, abstracts from the Pediatric Academic Societies' Annual Meetings (2000 to 2012) were searched on the website PAS2View(TM) as was the Web of Science website using the two previously identified trials as starting points.

Selection criteria: Randomised or quasi-randomised controlled clinical trials involving preterm infants. Initiation of cromolyn sodium administration during the first two weeks of life. The intervention had to include administration of cromolyn sodium by nebuliser or metered dose inhaler with or without spacer device versus placebo or no intervention. Eligible studies had to include at least one of the following outcomes: overall mortality, CLD at 28 days, CLD at 36 weeks' postmenstrual age (PMA), or the combined outcome mortality or CLD at 28 days.

Data collection and analysis: The standard method for The Cochrane Collaboration as described in the Cochrane Handbook for Systematic Reviews of Interventions was used. Risk ratio (RR) and risk difference (RD) with 95% confidence intervals (CI) are reported for dichotomous outcomes and weighted mean difference (WMD) for continuous data. A fixed-effect model was used for meta-analysis. Heterogeneity was examined using the I(2) statistic.

Main results: Two eligible studies were identified with small numbers of infants enrolled. Prophylaxis with cromolyn sodium did not result in a statistically significant effect on the combined outcome of mortality or CLD at 28 days; CLD at 28 days or at 36 weeks' PMA; or CLD in survivors at 28 days or at 36 weeks' PMA. Prophylaxis with cromolyn sodium did not show a statistically significant difference in overall neonatal mortality, incidence of air leaks, necrotising enterocolitis, intraventricular haemorrhage, sepsis, and days of mechanical ventilation. No side effects were noted. Further research does not seem to be justified.

Authors' conclusions: There is currently no evidence from randomised trials that cromolyn sodium has a role in the prevention of CLD. Cromolyn sodium cannot be recommended for the prevention of CLD in preterm infants.