#OA2-AM25-ST-08 - Pre-Transfusion Platelet Counts and Bleeding in Very Low Birth Weight Infants

Platelet transfusion (Plt Tx) thresholds for very low birth weight (VLBW, < 1500g) infants vary widely. It is unclear how differences in clinician practices related to Plt Tx thresholds are associated with bleeding in VLBW infants. We evaluated how bleeding may be associated with pre-Tx Plt counts in the first 3 postnatal weeks among VLBW infants.

Study

Design/Methods:

We conducted an observational birth cohort study of VLBW infants born in 8 U.S. hospitals from 4/2019-12/2023 as part of the Recipient Epidemiology and Donor Evaluation Study-IV-Pediatric (REDS-IV-P). Excluding surgical patients, VLBW infants who received at least 1 Plt Tx in the first 3 postnatal weeks were included. ICD-10 codes and clinical data submitted to the Vermont Oxford Network were used to identify the major types of bleeding in these infants, including intraventricular hemorrhage (IVH), gastrointestinal bleeding, pulmonary hemorrhage, and other bleeding. To account for within-infant correlation, we used mixed effects multivariable linear regression to test whether mean pre-Tx Plt counts differed among infants with and without bleeding. Models included adjustment for gestational age, postnatal age, and hospital.

Results/Findings: We evaluated 221 VLBW infants who received at least 1 Plt Tx during the first 3 postnatal weeks, for a total of 686 Plt Tx events. Eleven infants and 37 Plt Txs were excluded due to a missing pre-Tx Plt count within 24 hours of Tx. Of the 210 included infants, 39% were female sex, and 63% were born at < 24 weeks gestational age. 76% of these infants had documented bleeding, with IVH being the most common (61%), followed by other bleeding (26%), pulmonary hemorrhage (19%), and GI bleeding (10%). Most Plt Txs were given in the 1st postnatal week (71%). The overall mean pre-Tx Plt count was 56 x 10⁹/L among infants with any bleeding compared to 59 x 10⁹/L among infants without bleeding (adjusted mean difference -2 x 10⁹/L; 95% CI -14, 10; P=0.71). Similar findings of no significant difference in pre-Tx Plt between groups were seen when using large volume RBC Tx of >20 ml/kg as a surrogate for bleeding (P=0.32) and when evaluating only the first platelet transfusion (P=0.69). Increasing gestational age (P=0.002) and postnatal age (p=0.03) were both associated with lower pre-Tx Plt counts. Among different types of bleeding, only infants with severe IVH had higher pre-Tx Plt counts compared to infants without severe IVH (adjusted mean difference 15 x 10⁹/L; 95% CI 3, 28; P=0.01, Figure 1).

Conclusions: We found similar pre-Tx Plt counts among VLBW with most types of bleeding, although those with severe IVH had modestly higher pre-Tx Plt counts. These findings suggest that pre-Tx Plt counts are not associated with bleeding, except for severe IVH, in VLBW infants.