Table 3.

Marginal Effects from Generalized Linear Models Predicting Direct Costs (in USD), N = 425

	Marginal Effect (USD)	p-value
Brain injury	12,048	0.005
NEC	15,440	0.005
BPD	31,565	<0.001
Late onset sepsis	10,055	<0.001

Notes:

Abbreviations: Brain injury includes the presence of one of the following: intraventricular hemorrhage, periventricular leukomalacia, or acquired hydrocephalus; NEC = necrotizing enterocolitis; BPD = bronchopulmonary dysplasia. Regression models fit with a gamma distribution and log link. Models control for birth weight, gestational age, race/ethnicity, gender, and primary payer source. Direct costs, payments and charges adjusted to 2009 US dollars. The marginal effect represents the difference in adjusted direct costs when the morbidity is present compared to costs when none of the morbidities are present.