259 - Frequent Interfacility Transfer of Very Low Birthweight (VLBW) Infants During Birth Hospitalization

Poster Number: 259
Publication Number: 259.1918

Background: Interfacility transfer can match the needs of VLBW infants to available resources at a given hospital. However, VLBW transfers have high risks and costs due to patient complexity, impacting health system function and outcomes. Few studies have investigated the medical and hospital factors associated with VLBW transfer variation.

Objective: To characterize variation in US State VLBW transfer rate, compare infants with and without transfer by characteristics and outcomes, and analyze transfer patterns.

Design/Methods: We utilized linked birth and death certificates matched with maternal and newborn hospital records from California, Michigan, Oregon, Pennsylvania, and South Carolina to construct a cohort of infants with birthweight < 1,500 g and gestational age (GA) 22-43 weeks born 2000-2020. We defined transfer as hospital discharge and subsequent admission within 1 day. We assessed State hospital-level and infant-level transfer rates. With univariate and multivariate models, we compared infants with and without transfer by demographics, health conditions, procedures, and complications; maternal demographics and pregnancy complications; and hospital details. Amongst transferred infants, we assessed transfer type (higher, same, or lower level of care [LOC]), number, timing, and pattern.

Results: Amongst 166,896 VLBWs, the infant-level transfer rate was 19% (range 9-23% across States). Hospital-level transfer rate varied widely (Figure 1). Transferred VLBWs were more often < 28 weeks GA (48 vs 38%), < 1,060 g at birth (56 vs 48%), hospitalized longer (77 vs 49 days), and on government insurance (56 vs 49%) (p < 0.001). They were born at hospitals with less total (3,011 vs 3,546 births) and VLBW births (51 vs 74 births) (p < 0.001). They also had more sequalae of prematurity, complications, and procedures but lower mortality and pregnancy complications (Table 1). Each of these factors was associated with increased transfer rates in multivariate logistic regression with severe neurological procedures the strongest clinical predictor of transfer (OR 2.3, 95%CI 2.1-2.5). 25% of transferred VLBWs transferred multiple times; first transfers to higher LOC occurred earliest, followed by same and lower (13, 22, and 28 days). Amongst VLBWS with multiple transfers, transfers alternated between higher and lower LOC units (Table 2).

Conclusion(s): VLBWs transfer frequently and those who do are young, small, and sick. However, transfer occurrence and pattern are also strongly influenced by birth State, hospital, and NICU. Neonatal system regionalization and development are key determinants of VLBW transfer patterns.