Estimating the effect of diuretics and inhaled corticosteroids for evolving bronchopulmonary dysplasia in preterm infants

Abstract Background Off‐label treatment of extremely preterm infants with diuretics and inhaled corticosteroids (ICS) for evolving bronchopulmonary dysplasia (BPD) is common. Their effectiveness in reducing mortality or BPD severity, and optimal treatment timing, are unclear. Objectives To determine whether diuretic treatment or ICS administration for infants with early evolving (between 10–27 days postnatal) and progressively evolving (28th‐day–36th‐week postnatal) BPD are independently associated with reduced mortality and moderate or severe BPD at 36‐weeks postmenstrual age (PMA). Methods We examined neonates born before 28 weeks' gestation and admitted to neonatal intensive care units on postnatal Day 0 between 2006 and 2016 using data collected during routine care recorded within the Paediatric Health Information System (PHIS). An early evolving BPD cohort consisted of infants treated with oxygen, positive pressure or mechanical ventilation at 10 days postnatal. The progressively evolving BPD cohort consisted of infants treated with these modalities at 28 days. In new users, we evaluated the effect of diuretic and ICS treatment on mortality or BPD severity at 36 weeks PMA, adjusting for time‐dependent confounding by respiratory status using marginal structural models. Results Early evolving BPD was present in 10,135 patients; progressively evolving BPD in 11,728. New diuretic exposure during early evolving BPD (adjusted risk ratio [aRR] 0.77, 95% confidence interval [CI] 0.65, 0.93) was associated with decreased mortality or moderate/severe BPD risk. New diuretics (aRR 0.86, 95% CI 0.75, 0.99) during progressively evolving BPD between 28‐days–36‐weeks PMA were less strongly associated with mortality or moderate/severe BPD reduction. There was no strong association for ICS in patients with early evolving (aRR: 1.40; 95% CI: 0.79, 2.51) or progressively evolving BPD (aRR 1.16, 95% CI 0.95, 1.49). Conclusion Diuretics, but not ICS, for evolving BPD were associated with mortality and BPD risk reduction.