To evaluate the healthcare costs attributed to major morbidities associated with prematurity, namely, bronchopulmonary dysplasia (BPD), intraventricular hemorrhage, necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP), and nosocomial infections.

This was a retrospective analysis of infants born at 24-30 weeks of gestation, admitted to children's hospitals in the Pediatric Health Information System between 2009 and 2018. Charges were adjusted by geographical price index, converted to costs using cost-to-charge ratios, inflated to 2018 US$, and total costs were accumulated for the initial hospitalization. Quantile regressions, which are less prone to bias from extreme outliers, were used to examine the incremental costs attributed to each morbidity across the entire cost distribution, including the median.

There were 19 232 patients from 30 children's hospitals who were eligible. Higher costs were seen in lower gestational age, more severe morbidity, and those with higher number of comorbidities. Patients with surgical NEC, severe ROP, and severe BPD were the costliest with median total costs of $430 860, $413 825, and $399 495, respectively. Quantile regressions showed surgical NEC had the highest adjusted median incremental total cost ($48 621; 95% CI, $39 617-$57 626) followed by severe BPD ($35 773; 95% CI, $32 018-$39 528) and severe ROP ($22 561; 95% CI, $16 699-$28 423). Quantile regressions also revealed that surgical NEC, severe BPD, and severe ROP had increasing incremental costs at higher total cost percentiles, indicating these morbidities have a greater cost impact on the costliest patients.

Severe BPD, surgical NEC, and severe ROP are the costliest morbidities and contribute the most incremental costs especially for the higher costs patients.