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

Objective: To study the association between reduced use of postnatal steroids for bronchopulmonary dysplasia (BPD) in very low birthweight (VLBW) infants and oxygen (O₂)-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 O₂ 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 O₂ 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 O₂ 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 O₂ therapy was modest in degree.