Heterogeneity of Treatment Effects of Hydrocortisone by Risk of Bronchopulmonary Dysplasia or Death Among Extremely Preterm Infants in the National Institute of Child Health and Human Development Neonatal Research Network Trial: A Secondary Analysis of a Randomized Clinical Trial

Authors

Samuel J. Gentle, Department of Pediatrics, University of Alabama at Birmingham
Matthew A. Rysavy, Department of Pediatrics, University of Texas Health Science Center at Houston
Lei Li, Statistics and Epidemiology Division, RTI International, Research Triangle Park, North Carolina
Matthew M. Laughon, Department of Pediatrics, University of North Carolina at Chapel Hill
Ravi M. Patel, Department of Pediatrics, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, Georgia
Erik A. Jensen, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
Susan Hintz, Department of Pediatrics, Division of Neonatal and Developmental Medicine, Stanford University School of Medicine and Lucile Packard Children's Hospital, Palo Alto, California
Namasivayam Ambalavanan, Department of Pediatrics, University of Alabama at Birmingham
Waldemar A. Carlo, Department of Pediatrics, University of Alabama at Birmingham
Kristi Watterberg, Department of Pediatrics, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
National Institute of Child Health and Human Development Neonatal Research Network

Document Type

Article

Publication Date

5-1-2023

Abstract

IMPORTANCE: Extremely preterm infants who develop bronchopulmonary dysplasia (BPD) are at a higher risk for adverse pulmonary and neurodevelopmental outcomes. In the National Institute of Child Health and Human Development Neonatal Research Network (NICHD NRN) Hydrocortisone Trial, hydrocortisone neither reduced rates of BPD or death nor increased rates of neurodevelopmental impairment (NDI) or death.

OBJECTIVE: To determine whether estimated risk for grades 2 to 3 BPD or death is associated with the effect of hydrocortisone on the composite outcomes of (1) grades 2 to 3 BPD or death and (2) moderate or severe NDI or death.

DESIGN, SETTING, AND PARTICIPANTS: This secondary post hoc analysis used data from the NICHD NRN Hydrocortisone Trial, which was a double-masked, placebo-controlled, randomized clinical trial conducted in 19 US academic centers. The NICHD HRN Hydrocortisone Trial enrolled infants born at a gestational age of less than 30 weeks who received mechanical ventilation for at least 7 days, including at the time of enrollment, and who were aged 14 to 28 postnatal days. Infants were enrolled between August 22, 2011, and February 4, 2018, with follow-up between 22 and 26 months of corrected age completed on March 29, 2020. Data were analyzed from September 13, 2021, to March 25, 2023.

INTERVENTION: Infants were randomized to 10 days of hydrocortisone or placebo treatment.

MAIN OUTCOMES AND MEASURES: Infants' baseline risk of grades 2 to 3 BPD or death was estimated using the NICHD Neonatal BPD Outcome Estimator. Differences in absolute and relative treatment effects by baseline risk were evaluated using interaction terms in models fitted to the efficacy outcome of grades 2 to 3 BPD or death and the safety outcome of moderate or severe NDI or death by follow-up.

RESULTS: Among the 799 infants included in the analysis (421 boys [52.7%]), the mean (SD) gestational age was 24.9 (1.5) weeks, and the mean (SD) birth weight was 715 (167) g. The mean estimated baseline risk for grades 2 to 3 BPD or death was 54% (range, 18%-84%) in the study population. The interaction between treatment group and baseline risk was not statistically significant on a relative or absolute scale for grades 2 to 3 BPD or death; the size of the effect ranged from a relative risk of 1.13 (95% CI, 0.82-1.55) in quartile 1 to 0.94 (95% CI, 0.81-1.09) in quartile 4. Similarly, the interaction between treatment group and baseline risk was not significant on a relative or absolute scale for moderate or severe NDI or death; the size of the effect ranged from a relative risk of 1.04 (95% CI, 0.80-1.36) in quartile 1 to 0.99 (95% CI, 0.80-1.22) in quartile 4.

CONCLUSIONS AND RELEVANCE: In this secondary analysis of a randomized clinical trial, the effect of hydrocortisone vs placebo was not appreciably modified by baseline risk for grades 2 to 3 BPD or death.

TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01353313.

Publication Title

JAMA Netw Open

ISSN

2574-3805

Volume

6

Issue

5

First Page

2315315

Last Page

2315315

DOI

10.1001/jamanetworkopen.2023.15315

Recommended Citation

Gentle SJ, Rysavy MA, Li L, Laughon MM, Patel RM, Jensen EA, Hintz S, Ambalavanan N, Carlo WA, Watterberg K; National Institute of Child Health and Human Development Neonatal Research Network. Heterogeneity of Treatment Effects of Hydrocortisone by Risk of Bronchopulmonary Dysplasia or Death Among Extremely Preterm Infants in the National Institute of Child Health and Human Development Neonatal Research Network Trial: A Secondary Analysis of a Randomized Clinical Trial. JAMA Netw Open. 2023 May 1;6(5):e2315315. doi: 10.1001/jamanetworkopen.2023.15315. PMID: 37256621; PMCID: PMC10233424.