Abstract
IMPORTANCE: Infants born extremely preterm receive transfusions at higher platelet count thresholds than older children and adults due to concerns for intracranial hemorrhage. A recent randomized trial comparing 2 platelet transfusion thresholds showed the higher threshold was associated with increased risk of long-term adverse neurodevelopmental outcomes. OBJECTIVE: To evaluate the association of platelet transfusion exposure with death and severe neurodevelopmental impairment (NDI) at 2 years' corrected age in a cohort of infants born extremely preterm. DESIGN, SETTING, AND PARTICIPANTS: An observational cohort study and secondary analysis of the Preterm Erythropoietin Neuroprotection Trial, a randomized, placebo-controlled clinical trial of erythropoietin neuroprotection in neonates born extremely preterm, was conducted in 30 neonatal intensive care units in the US from December 1, 2013, to September 31, 2016. This analysis included 819 infants born extremely preterm at 24 to 27 completed weeks of gestation who had a documented outcome (death or neurodevelopmental assessment). Analysis was performed in April 2023. EXPOSURES: Any platelet transfusion during neonatal intensive care unit hospitalization. MAIN OUTCOMES AND MEASURES: The primary composite outcome was death or severe NDI evaluated at 2 years' corrected age using the Bayley Scales of Infant Development-Third Edition (BSID-III) and the Gross Motor Function Classification System and was defined as the presence of severe cerebral palsy or a BSID-III composite motor or cognitive score 2 SDs below the mean. Confounding by indication for platelet transfusion was addressed with covariate adjustment and propensity score methods. RESULTS: Of the 819 infants included in the analysis (429 [52.4%] male; mean [SD] gestational age, 25.5 [1.1] weeks), 245 (30.0%) received at least 1 platelet transfusion during their initial hospitalization. The primary outcome occurred in 46.5% (114 of 245) of infants exposed to a platelet transfusion and 13.9% (80 of 574) of nonexposed infants with a corresponding odds ratio of 2.43 (95% CI, 1.24-4.76), adjusted for propensity score, gestational age at birth, and trial treatment group. The individual components of death and severe NDI were directionally consistent with the overall composite outcome. CONCLUSIONS AND RELEVANCE: The findings of this study suggest that platelet transfusion in infants born extremely preterm may be associated with an increased risk of death or severe NDI at 2 years' corrected age, although the possibility of residual confounding by indication cannot be excluded.