Aims To determine the incidence of retinopathy of prematurity (ROP) based upon a national database and to identify baseline characteristics, demographic information, comorbidities, and surgical interventions.

Methods The National Inpatient Sample, a representative sample of all US hospital discharges from 1997 to 2002, was queried for all newborn infants with and without ROP. Primary outcome variables included demographics, comorbidities, hospital length of stay (LOS), and hospital charges. Multivariate logistic regression was used to predict risk factors for ROP.

Results 4.67 million live births were recorded during the study period. The total incidence of ROP was 0.12% overall and 7.35% for premature infants with LOS greater than 14 days. Newborns with ROP were more likely to be born at a teaching hospital and to have higher LOS and hospitalisation charges. The odds ratios for the development of ROP were greatest in infants weighing less than 1250 grams. The multivariate regression model revealed that only respiratory distress and intraventricular haemorrhage were predictive of the development of ROP and Hispanic infants were 33% more likely to develop ROP.

Conclusion This study represents the largest cohort of newborns analysed for ROP. The multivariate analysis emphasised the role of birth weight in extended-stay infants, as well as Hispanic race, respiratory distress syndrome, and intraventricular haemorrhage.