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

• Type of Material: Article
• Authors: Samuel J Gentle, The University of Alabama at Birmingham; Matthew A Rysavy, University of Texas Health Science Center at Houston; Lei Li, RTI International; Matthew M Laughon, University of North Carolina at Chapel Hill; Ravi Patel, Emory University; Erik A Jensen, The Children's Hospital of Philadelphia; Susan Hintz, Stanford University School of Medicine; Namasivayam Ambalavanan, The University of Alabama at Birmingham; Waldemar A Carlo, The University of Alabama at Birmingham; Kristi Watterberg, UNM Health Sciences Center
• Language: English
• Date: 2023-05-31
• Publisher: Emory University Libraries
• Publication Version: Final Published Version
• Copyright Statement: 2023 Gentle SJ et al. JAMA Network Open.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1001/jamanetworkopen.2023.15315
• Title of Journal or Parent Work: JAMA Network Open
• Volume: 6
• Issue: 5
• Start Page: E2315315
• End Page: E2315315
• Grant/Funding Information: The Neonatal Research Network (NRN), including the Hydrocortisone Trial for bronchopulmonary dysplasia, supported by grants U10 HD21373, UG1 HD21364, UG1 HD21385, UG1 HD27851, UG1 HD27853, UG1 HD27856, UG1 HD27880, UG1 HD27904, UG1 HD34216, UG1 HD36790, UG1 HD40492, UG1 HD40689, UG1 HD53089, UG1 HD53109, UG1 HD68244, UG1 HD68270, UG1 HD68278, UG1 HD68263, UG1 HD68284; UG1 HD87226, and UG1 HD87229 from the NIH and NICHD and grants UL1 TR6, UL1 TR41, UL1 TR42, UL1 TR77, UL1 TR93, UL1 TR105, UL1 TR442, UL1 TR454, and UL1 TR1117 from the National Center for Advancing Translational Sciences (NCATS).
• Keywords: Respiration, Artificial; Humans; Infant; Infant, Newborn; Male; National Institute of Child Health and Human Development (U.S.); Bronchopulmonary Dysplasia; Child; Infant, Extremely Premature; Hydrocortisone; United States
• Research Categories: Health Sciences, Medicine and Surgery; Health Sciences, Epidemiology

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.