Less postnatal steroids, more bronchopulmonary dysplasia: a population-based study in very low birthweight infants

Abstract

Objective: To study the association between reduced use of postnatal steroids for bronchopulmonary dysplasia (BPD) in very low birthweight (VLBW) infants and oxygen (O(2))-dependency at 28 days of age and at 36 weeks postmenstrual age.

Design: Large national database study.

Setting: The Israel National VLBW Neonatal Database.

Patients: The sample included infants born between 1997 and 2004, of gestational age 24-32 weeks, who required mechanical ventilation or O(2) therapy. Four time periods were compared: 1997-8 (era 1, peak use), 1999-2000 (era 2, intermediate), 2001-2 (era 3, expected reduction) and 2003-4 (era 4, lowest). The outcome variable "oxygen dependency" was based on clinical criteria. Multivariate regression models were used to account for confounding variables.

Results: Steroid use fell significantly from 23.5% in 1997-8 to 11% in 2003-4 (p<0.005). After adjustment for relevant confounding variables, the odds ratio for O(2) therapy at 28 days in era 4 versus era 1 was 1.75, 95% confidence interval (CI) 1.47 to 2.09 and 1.41, 95% CI 1.15 to 1.73 at 36 weeks postmenstrual age. The mean duration of O(2) therapy increased from 25.3 days (95% CI 23.3 to 26.3) in era 1, to 28.0 days (95% CI 26.6 to 29.4) in era 4. Survival increased from 78.5% in era 1 to 81.6% in era 4 (p<0.005).

Conclusions: The use of steroids has fallen considerably since the awareness of the adverse effects of this treatment. This change has been temporally associated with increased O(2) dependency at 28 days of age and at 36 weeks postmenstrual age. The prolongation of O(2) therapy was modest in degree.