108 - Time to Regain Birthweight and Association with In-Hospital Outcomes among Extremely Preterm Newborns in the United States

Poster Number: 108
Publication Number: 108.180

Background: The optimal time to regain birthweight (TRB) among extremely preterm (EP) newborns remains uncertain. TRB is a metric composed of time from birth to weight loss nadir (birth-to-nadir), time from weight loss nadir to regain birthweight (nadir-to-regain), and cumulative weight loss (CWL; a measure of percent weight loss from birthweight (BW) multiplied by total days of weight loss). While published national recommendations suggest longer TRB among preterm newborns is associated with malnutrition, our group has found that longer TRB, increasing CWL and a more rapid nadir-to-regain are associated with adverse neurodevelopmental outcomes at 2 years of age among EP newborns. It is unknown what, if any, association exists between TRB and its subcomponents with in-hospital outcomes among EP newborns.

Objective: We aimed to determine the association between TRB and its components with in-hospital outcomes among EP newborns.

Design/Methods: We conducted a secondary analysis of the Preterm Erythropoietin Neuroprotection Trial (PENUT), which enrolled EP newborns at 24w0d-27w6d across 30 US neonatal intensive care units (Table 1). Outcome analyses were performed evaluating quartiles of TRB, birth-to-nadir, nadir-to-regain, and CWL with in-hospital overall mortality, necrotizing enterocolitis, bronchopulmonary dysplasia, retinopathy of prematurity (ROP), and length of hospital stay after adjusting for known covariates using generalized estimating equations logistic or linear regression models.

Results: Among n=876 EP newborns, a TRB within 6-8 days was associated with significantly reduced odds of developing ROP when compared to TRB ≥12 days (aOR 0.38, 95% CI 0.17-0.85; Table 2). Birth-to-nadir and CWL were not associated with adverse outcomes or LOS in adjusted analyses A nadir-to-regain within 2-4 days was associated with longer LOS when compared to >7 days in unadjusted analyses, although did not reach statistical significance in adjusted analyses (2-4 days nadir-to-regain: 5.45 more days, 95% CI -3.34 to 14.2; Table 3).

Conclusion(s): TRB 6-8 days was associated with 62% reduced odds of developing ROP when compared to a longer TRB (≥12 days). In addition to previous findings suggesting shorter nadir-to-regain is associated with impaired 2-year neurodevelopmental outcomes, shorter nadir-to-regain may also be associated with adverse outcomes including longer hospitalization.