Two-year neurodevelopmental outcomes of extremely preterm infants treated with early hydrocortisone: treatment effect according to gestational age at birth

Objective: To determine whether early hydrocortisone treatment in extremely preterm infants affects neurodevelopmental outcomes at 2 years of age according to gestational age at birth.

Patients and methods: This is an exploratory analysis of neurodevelopmental outcomes by gestational age strata from the PREMILOC trial, in which patients were randomly assigned to receive either placebo or low-dose hydrocortisone and randomisation was stratified by gestational age groups (24-25 and 26-27 weeks of gestation). Neurodevelopmental impairment (NDI) was assessed using a standardised neurological examination and the revised Brunet-Lézine scale at 22 months of corrected age.

Results: A total of 379 of 406 survivors were evaluated, 96/98 in the gestational age group of 24-25 weeks and 283/308 in the gestational age group of 26-27 weeks. Among surviving infants born at 24-25 weeks, significant improvement in global neurological assessment was observed in the hydrocortisone group compared with the placebo group (P=0.02) with a risk of moderate-to-severe NDI of 2% and 18%, respectively (risk difference 16 (95% CI -28% to -5%)). In contrast, no statistically significant difference between treatment groups was observed in infants born at 26-27 weeks (P=0.95) with a similar risk of moderate-to-severe NDI of 9% in both groups. The incidence of cerebral palsy or other major neurological impairments were found similar between treatment groups in each gestational group.

Conclusions: In an exploratory analysis of neurodevelopmental outcomes from the PREMILOC trial, early low-dose hydrocortisone was associated with a statistically significant improvement in neurodevelopmental outcomes in infants born at 24 and 25 weeks of gestation.