This was a retrospective, population-based study of Florida resident infants with CCHD born 1998 to 2007 identified by the Florida Birth Defects Registry (FBDR). The FBDR is a passive, state-wide birth defects surveillance system that identifies infants with birth defects from multiple healthcare databases (Salemi et al., 2011, 2012). The FBDR primarily identifies infants with birth defects through hospital discharge records from Florida’s Agency for Health Care Administration (AHCA). AHCA collects admission, diagnosis, and facility charge information from all Florida hospitals and associated birth and surgical centers (AHCA, 2012). AHCA does not collect information from nonhospital based birthing centers, although 99% of births in Florida occur in hospitals (MacDorman et al., 2010). The FBDR includes information from state vital statistics and thus captures infant deaths that occur outside of hospitals. The FBDR does not capture information on adopted infants or those whose mothers delivered out-of-state (Salemi et al., 2011, 2012). This study was approved by Institutional Review Boards at the Florida Department of Health, the University of North Carolina at Charlotte, and the University of South Florida.

Our case definition included primary and secondary targets of CCHD screening. We defined timely CCHD detection as an International Classification of Disease, 9th revision; Clinical Modification (ICD-9-CM) code for screening-detectable CCHD diagnoses identified on the infant’s birth hospitalization discharge record. Seven CCHD conditions that usually present with hypoxemia are classified as primary targets for screening: hypoplastic left heart syndrome (ICD-9-CM: 746.7), pulmonary atresia (with intact septum) (746.01), dextrotransposition of the great arteries (745.10), truncus arteriosus (745.0), tricuspid atresia (TRA) (746.1), tetralogy of Fallot (745.2), and total anomalous pulmonary venous connection (747.41) (Mahle et al., 2009; Kemper et al., 2011). Other CCHD conditions that sometimes present with hypoxemia are considered secondary screening targets: coarctation/hypoplasia of aortic arch (747.10), double-outlet right ventricle (745.11), aortic interruption/atresia/hypoplasia (747.11, 747.22), Ebstein anomaly (746.2), and single ventricle (745.3) (Mahle et al., 2009; CDC, 2012; CDC, 2013). Available data did not distinguish whether infants received a pre- or postnatal diagnosis of CCHD. Infants were classified to have single CCHD (e.g., tetralogy of Fallot) or multiple CCHD (e.g., coarctation/hypoplasia of aortic arch and double-outlet right ventricle).

Inclusion criteria for this analysis were as follows: (1) infants had a CCHD ICD-9-CM code for at least one screening-detectable CCHD condition; (2) infants had a corresponding birth hospitalization discharge record with associated hospital charges from AHCA; and (3) if there was no CCHD diagnosis code on the birth hospitalization record, infants had at least one subsequent hospital admission or record of death due to any cause within the first year of life.

We analyzed the number of hospital admissions, number of hospitalized days, and estimated hospital costs based on hospitalizations initiated, but not necessarily completed, during the newborn (<28 days) and infant (<365 days) periods. Hospitalizations were assessed as continuous episodes of hospital care, regardless of whether a transfer occurred (Colvin and Bower, 2009). Multiple admissions were assessed as one hospitalization if an infant was admitted to a hospital on the same day as discharged from a previous admission, or if the infant was admitted to a hospital one day after a previous discharge with an accompanying “transfer” code. The level of birth hospitalization nursery care (I, III, or III [highest]) (American Academy of Pediatrics, 2004) that an infant received was coded as the highest facility level if a transfer occurred. Infants’ hospital discharge records identified the principal expected healthcare payer for each hospitalization as private or employer-based insurance (including TRICARE) or public insurance (Medicare, Medicaid, Veteran’s Administration, and Children’s Health Insurance Program, which is KidCare in Florida). Infants with mixed payer status had multiple payers for hospitalizations in the first year of life.

All dollar values are reported as 2011 U.S. dollars calculated using the Purchaser Price Index for hospitals (U.S. Bureau of Labor Statistics, 2012). AHCA reports inpatient facility charges, excluding professional fees. Based on state-level hospital data from the Agency for Healthcare Research and Quality’s State Inpatient Database, the average all-payer inpatient hospital cost-to-charge ratio among Florida hospitals for 2009 (n =217 hospital reporting) was 0.281, suggesting hospitals’ costs average approximately 28% of the amount those hospitals bill to healthcare payers (AHRQ, 2012). We converted patient charges to estimated costs using this statewide cost-to-charge ratio. Our analysis focused on relative comparisons of inpatient experiences for infants with timely and late detected CCHD; we did not attempt to estimate the total financial burden attributable to CCHD during infancy. We did not attempt to estimate the total financial burden attributable to CCHD during infancy.

Mortality among infants with late detected CCHD was classified as: (1) Nonhospital death without hospital readmission =infant died following birth hospitalization without any subsequent hospital readmissions; (2) Death upon emergent readmission after birth hospitalization =infant died within 3 days of an “emergency” or “urgent” inpatient admission following birth hospitalization; and (3) Other death during infancy =all other deaths among infants with late detected CCHD during the first year of life. Deaths under the first two circumstances might be avoidable through timely CCHD detection with screening done at the birth hospital. Based on available data, we were not able to further investigate additional circumstances in which mortality might be avoided. In multivariable analyses described below, we controlled for mortality when assessing the relative financial impact of late CCHD detection.

We assessed inpatient hospital resource use for the newborn and infant periods in terms of number of admissions, hospitalized days, and estimated costs. We report mean and median estimates for each measure of hospital use. Because hospital resource use indicators were right-skewed (meaning, a low number of infants had a high number of hospital admissions, number of hospitalized days, and estimated inpatient costs), the mean exceeds the median for each measure. Mean cost is used in economic analyses because total cost is the product of mean cost per case and the number of cases. Median costs might be useful, for example, to project the expected healthcare use of an individual infant. Mean cost measures are relevant for population-level analyses and are the primary focus of this study.

We compared mean hospital resource use between newborns and infants with timely versus late detected CCHD using sum rank tests. Because factors related to timely CCHD detection could drive observed mean group differences (e.g., timely detected CCHD could be more severe, leading to greater resource use), we used linear regression models to examine associations between late CCHD detection and hospital resource use that controlled for selected maternal/household and infant characteristics. Maternal/household characteristics included: maternal age, race/ethnicity, nativity, education, and expected principal healthcare payer status during the infant’s first year of life. Infant characteristics included: sex, preterm birth, noncardiac congenital anomalies, death during infancy, birth hospitalization nursery care level, and type of CCHD. The continuous measures of hospital resource use indicators (i.e., number of hospitalized days) were log-transformed for the analysis. Because of the transformation, model results are reported as exp(β) and interpreted as percentage changes in the dependent variables associated with unit changes in the (non–log-transformed) independent variables (Vittinghoff et al., 2012). All models controlled for infants’ birth year.

Approximately 23% (n =825/3603) of infants had late detected CCHD, meaning no CCHD diagnosis code appeared on the birth hospitalization discharge record (Table 2). Among infants with one of the seven CCHD conditions considered a primary target of newborn screening, 21% (n =348/1639) were late detected. The median age of detection in an inpatient setting among infants with late detected CCHD was 88 days (range: 2–364). Overall, 18% of infants with CCHD died during infancy (Table 3). Among infants with timely detected CCHD, 20% (n =568/2778) died during infancy, compared with 8% (n =66/825) of infants with late detected CCHD, unadjusted for clinical characteristics. Among infants with late detected CCHD, 0.8% (n =7/825) died outside of a hospital following the birth hospitalization without readmission and 1% (n =8/825) died upon emergent hospital readmission. This equates to an estimated potentially avoidable mortality of 0.4% (n =15/ 3603) among all infants with CCHD once universal screening is implemented.

Based on a simple comparison of means, during the neonatal period newborns with late detected CCHD had significantly more hospital admissions compared with infants with timely detected CCHD (1.3 vs. 1.0 admissions, respectively) (Table 4), although newborns with late detected CCHD had significantly fewer hospitalized days for admissions initiated during the neonatal period (15.3 vs. 27.3 days, respectively) (Table 4) and lower estimated inpatient costs (approximately $31,300 vs. $72,000, respectively) (Table 5). This pattern was consistent when hospitalizations initiated any time during infancy were analyzed. Infants with late detected CCHD had significantly more hospital admissions during the entire first year of life compared with infants with timely detected CCHD (3.0 vs. 2.1 admissions, respectively) (Table 4), although fewer hospitalized days (30.1 vs. 37.5 days, respectively) (Table 4), and lower estimated inpatient costs (approximately $69,500 vs. $100,200, respectively) (Table 5).

The overall picture of greater inpatient resource use among infants with timely detected CCHD changed in the multivariable analysis that assessed all of infancy. First, during the newborn period and controlling for selected characteristics, late CCHD detection was significantly associated with 16% more hospital admissions during the newborn period but 38% fewer hospitalized days and 63% lower estimated inpatient costs (Table 6). However, for all of infancy, late CCHD detection was associated with 52% more admissions, 18% more hospitalized days, and 35% higher inpatient costs during infancy. Relative to hypoplastic left heart syndrome, only multiple CCHD was associated with higher estimated inpatient costs during infancy. Preterm birth and the presence of a noncardiac congenital anomaly were associated with 12% and 45% higher estimated inpatient costs during infancy, respectively. Infant death was associated with 22% lower estimated inpatient costs during infancy. Compared with Level III nursery care, Level I or II care during the birth hospitalization were each associated with over 60% lower estimated inpatient costs during infancy. Younger maternal age (<25 years old) was significantly associated with lower estimated inpatient costs during infancy relative to mothers 25 to 34 years old. Non-Hispanic black and Hispanic mothers of children with CCHD had higher inpatient costs during infancy compared with non-Hispanic white mothers. Relative to infants with private hospital payer sources, infants with public or mixed payer sources had significantly higher estimated inpatient costs and infants with no insurance had significantly lower estimated inpatient costs (Table 5).