Background Trisomy 21, 18, and 13 are the three most commonly diagnosed autosomal trisomies in liveborn infants. Affected infants frequently have serious or fatal comorbid birth defects. Published rates of comorbid birth defects among trisomies are dated and based on very limited numbers of infants.
Research Objective To use a large national hospital discharge database to characterize comorbidities associated with trisomy 21, 18, and 13 among U.S. newborns.
Design/Methods Analyses are based on hospital discharges from 1988 through 2002. All newborn discharges with ICD-9 diagnoses for trisomy 21, 18, and 13 were selected from the annual National Inpatient Survey (NIS) or Kids' Inpatient Database (KID), which are both products of the Healthcare Cost and Utilization Project (HCUP). The NIS is based on a 20% sample of short-term and community hospital discharges from participating states for a particular year. The KID is an 80% sample of all pediatric discharges for 1997 and 2000 from participating states. Percentages of infants with any of 43 commonly reported comorbid birth defects were calculated. To avoid double counting, only those hospitalizations occurring during the first 10 days of life were included, and hospital transfers were excluded.
Results Population rates for the three trisomy conditions were comparable to or slightly lower than previous estimates. Trisomy 21 was identified in 14,650 newborns. The most common comorbidities were heart defects 41% (PDA 22%, ASD 16%, VSD 12%, endocardial cushion defect 10%). Trisomy 18 was identified in 1,776 newborns. The most common comorbidities were heart defects 50% (VSD 32%, PDA 23%, ASD 12%), and musculoskeletal defects 11%. Trisomy 13 was identified in 1,177 newborns. The most common comorbidities were heart defects 42% (PDA 20%, VSD 18%, ASD 11%, TOF 7%), orofacial defects 26% (cleft lip 21%, cleft palate 5%), and musculoskeletal defects 22%. Among infants with trisomy 21, 3% died prior to discharge. Among trisomy 18 newborns, 54% died in the hospital, and among trisomy 13, 56% died prior to discharge.
Conclusions Common comorbid diagnoses of trisomies 21, 18, and 13 include serious and readily identifiable disorders that are associated with increased morbidity and mortality. This updated and more complete information on comorbid conditions can be used to inform clinical decision making and help providers better prepare families for infants with trisomies.