Supplementary Material for: Association between early postnatal hydrocortisone and retinopathy of prematurity in extremely preterm infants

ABSTRACT
Introduction
Retinopathy of prematurity (ROP) is a leading cause of preventable childhood blindness. We investigated the association of early postnatal low-dose intravenous hydrocortisone used for the prevention of bronchopulmonary dysplasia (BPD) with ROP-outcome among extremely preterm infants in a Swedish cohort.
Methods
This retrospective cohort study included extremely preterm infants born before 28 weeks of gestational age (GA). Infants born September 2020 - August 2022, treated with low-dose intravenous hydrocortisone for prevention of BPD, were compared to untreated controls born September 2016 - August 2020. Hydrocortisone was administered postnatally with a dose of 0.5 mg/kg twice daily for seven days, followed by 0.5 mg/kg per day for three days.
Logistic regression, adjusted for GA, birth weight (BW), sex, and parenteral nutrition, was used in the primary analysis. For robustness we performed 1:1 propensity score (PS) matching followed by logistic regression.
Results
Of 245 preterm infants included, 65 were treated with low-dose hydrocortisone and 180 were untreated controls. Incidence of ROP treatment was reduced in the hydrocortisone group 18.5% (12/65) versus controls 32.2% (58 /180), p=0.038. One-to-one PS-matching (n= 62+62) confirmed the reduced incidence of ROP treatment in the hydrocortisone-treated infants (OR 0.38, 95% CI 0.16 - 0.88, p=0.025). After adjusting for GA, BW, sex, and parenteral nutrition ≥14 days the reduced risk of ROP treatment after early hydrocortisone treatment persisted (OR 0.31, 95% CI 0.16 - 0.60, p=0.0005).
Conclusion
Early postnatal low-dose intravenous hydrocortisone used to prevent BPD may reduce the risk of ROP treatment among extremely preterm infants.