Administering platelet transfusions to preterm infants with severe thrombocytopenia at a platelet count threshold of 25,000 per cubic millimeter rather than 50,000 per cubic millimeter may lead to lower mortality, according to research published in the New England Journal of Medicine.

Researchers enrolled 653 infants with a median gestational age of 26.6 weeks (range, 22.7-33.9) and platelet counts below 100,000 per cubic millimeter. Of these infants, 322 were randomly assigned to receive platelet transfusions when their platelet count fell below 50,000 per cubic millimeter (high threshold group) and 329 were randomly assigned to receive platelet transfusions when their platelet count fell below 25,000 (low threshold group). In total, 90% of high-threshold infants and 53% of low-threshold infants received at least 1 transfusion.

The primary outcome was death or major bleeding within 28 days of random assignment. Secondary outcomes included number of platelet transfusion episodes; retinopathy of prematurity; serious adverse events; and rate, severity, and time-to-bleeding episodes. Bleeding episodes were graded as minor, moderate, major, or severe using a validated bleeding assessment tool developed for this trial.

Overall, 26% of high-threshold infants and 19% of low-threshold infants died or experienced major bleeding by day 28 (odds ratio, 1.57; P =.02). Analysis of mortality only yielded a similar odds ratio. The researchers found no significant differences in the rates of minor or worse bleeding, retinopathy of prematurity, or survival between groups.

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In the high-threshold group, 81 infants (25%) experienced 91 serious adverse events; in the low-threshold group, 74 infants (22%) experienced 92 serious adverse events (odds ratio, 1.14). This difference was not statistically significant.

The authors predicted that “reducing the transfusion trigger from 50,000 per cubic millimeter to 25,000 per cubic millimeter may prevent death or major bleeding in 7 of 100 preterm neonates with severe thrombocytopenia.” However, they cautioned that the mechanisms underlying this difference in event rates between groups remained unknown.

Reference

1. Curley A, Stanworth SJ, Willoughby K, et al. Randomized trial of platelet-transfusion thresholds in neonates [published online January 17, 2019]. N Engl J Med. doi: 10.1056/NEJMoa1807320