Assessment of social factors influencing hospitalization cost of US preterm newborns, 2016.

Background and objective: Preterm newborn (PTN) care is costly in the US, and the preterm birth (PTB) rate has not seen substantial improvement. PTB remains a significant public health issue because of risks of adverse health outcomes and the associated economic burden. Assessing factors leading to high hospital cost is imperative in order to ease economic burden associated with PTB. Social factors influencing hospitalization cost for PTN have not been studied extensively. This study aims to examine the contributions of hospital type, race/ethnicity, and median household income quartile to the cost of the PTN's initial hospitalization after birth.Materials and methods: Data used in this study originated from the 2016 Healthcare Cost and Utilization Project Kids' Inpatient Database (KID) which provided the most recent national records of pediatric hospitalization in the US. International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes P07.2x and P07.3x were used to identify birth gestational age (GA) in complete weeks. Q00-Q99 codes were used to identify congenital anomalies. Data records reflecting hospitalization of newborns without congenital anomalies were extracted to estimate total cost in 2016. Analysis of factors influencing total cost was performed on the subset of newborns that were in-born and with birth GA from 24 to 36 weeks. Total hospital cost was calculated by multiplying total charges and cost-to-charge ratios. Per-diem cost was calculated by dividing total hospital cost by length of stay. Linear regression modeling was performed using weighted data, and the best model was selected using the Akaike information criteria. Results: Hospitalization cost for PTNs, who constituted 7.6% of all studied newborns, comprised 45% of total newborn hospitalization cost. PTNs in freestanding children's hospitals had significantly higher total cost compared to non-children's teaching and non-teaching hospitals. The cost difference was GA-dependent. The latter two hospital types reported similar cost for PTNs. Although race/ethnicity and median household income quartile were related, the two covariates had independent effects on total hospitalization cost. A model built to assess the roles of covariates in the association between GA and total hospitalization cost found that all three covariates independently affected total cost when controlling for one another, with hospital type also showing an interaction effect with GA.Conclusions: Hospitalization cost is highly influenced by hospital type, race/ethnicity, and median household income quartile. The modifiable aspects of these factors may be further dissected and targeted in order to ease the burden of high hospitalization cost associated with PTB.