The Interaction between Major Birth Defects and Preterm Birth in Infant Healthcare Expenditures: Implications for Assessments of the Benefits of Prevention
Methods: We used DRG codes in MarketScan® claims data to identify live births during 2013 who had 12 months continuous non-capitated plan enrollment. Preterm birth (<37 weeks) and selected major birth defects (MBDs) were ascertained using ICD-9-CM and DRG codes, which have limitations.
Results: Among 56,183 privately insured infants, 1,458 (2.6%) were classified with a MBD, 4,616 (8.2%) were preterm, and 349 (0.6%) infants were born preterm with a MBD. Among non-preterm infants, mean healthcare cost was $58,059 higher with MBDs. Conversely, among infants born preterm, mean cost was $200,263 higher with MBDs. Subtracting the former from the latter, the incremental cost of preterm birth was $142,204 among infants with MBDs. The incremental cost of preterm birth was $41,746 without MBDs. Overall, preterm infants cost $56,016 more on average than non-preterm infants, or $49,341 controlling for MBDs, calculated as the weighted average of the incremental costs of preterm birth among infants with and without MBDs.
Discussion: Adjusting for the interaction of preterm birth and MBDs reduced the mean incremental healthcare cost of preterm birth in this sample by 13-14%. Further analysis of costs of early and late preterm birth among infants with specific MBDs is needed.