Respiratory Illness and Costs Linger for Years in Preterm Babies After NICU Discharge

For parents of a premature baby, the day of discharge from the neonatal intensive care unit often feels like crossing a finish line. A new study suggests it is better understood as the start of a long and medically expensive marathon. Researchers tracking thousands of US infants born preterm with neonatal respiratory distress syndrome found that respiratory illness, frequent healthcare use and substantial costs persisted long after the birth hospitalization ended, even among children who never received a diagnosis of bronchopulmonary dysplasia, the chronic lung disease typically associated with prolonged neonatal respiratory problems.

The study, published in BMC Pediatrics, was led by Steven H. Abman of the University of Colorado School of Medicine and Children’s Hospital Colorado, together with colleagues from Chiesi and IQVIA. It took a real-world approach to a question that clinical trials rarely address: what happens to these infants after they leave intensive care? While the short-term course of neonatal respiratory distress syndrome is well documented, the longer respiratory trajectory of surviving infants has remained surprisingly murky, leaving clinicians without a clear picture of how much follow-up care the population actually needs.

To answer it, the team assembled a retrospective cohort using three linked US databases: the IQVIA Hospital Charge Data Master, Professional Fee Claims, and Longitudinal Prescription Claims records, spanning October 2015 through March 2024. The researchers identified 7,532 preterm infants, all born before 37 weeks of gestation, who were diagnosed with neonatal respiratory distress syndrome between October 2015 and March 2022 and treated with either exogenous surfactant or continuous positive airway pressure during their birth hospitalization. Follow-up began at discharge and continued for at least three months, with a median follow-up of about one year, a design that captures the earliest and often most vulnerable period of childhood respiratory development.

The cohort was divided into three gestational age strata that mirror standard neonatal categories. Very preterm infants, born before 32 weeks, made up 32.3 percent of the sample; moderate preterm infants, between 32 and 34 weeks, accounted for 23.7 percent; and late preterm infants, between 34 and 37 weeks, represented the largest share at 43.6 percent. This stratification matters because gestational age is one of the strongest predictors of both lung maturity and long-term respiratory outcomes, allowing the researchers to see how the burden of disease scales with early birth.

The headline finding is the sheer persistence of respiratory morbidity. Nearly half of the infants, 49.6 percent, were documented with at least one upper respiratory tract infection during follow-up, while 32.4 percent had cough, 31.5 percent had lower respiratory tract infections, and 28.6 percent developed bronchiolitis, an inflammation of the small airways that is a leading cause of infant hospitalization. In other words, respiratory illness was the norm rather than the exception in this population, affecting infants across every gestational age group in the study.

The pattern of illness shifted in a telling way across the gestational age spectrum. Acute, self-limited infections such as upper and lower respiratory tract infections, bronchiolitis and cough were actually more frequent among moderate and late preterm infants, possibly reflecting differences in exposure and healthcare contact. But the more chronic and ominous diagnoses clustered in the very preterm group: asthma, pulmonary hypertension, obstructive sleep apnea, pneumonia and persistent wheeze all occurred most often in infants born before 32 weeks. That gradient suggests that the deepest prematurity leaves a durable imprint on lung structure and function that continues to manifest well beyond infancy, not merely as transient infections but as conditions with lifelong implications.

Healthcare utilization told the same story from a different angle. During follow-up, 62.2 percent of the children used outpatient pharmacy services, 40.3 percent had physician office visits, and 30.8 percent were seen in emergency rooms for respiratory reasons, with broadly similar patterns across all three gestational age groups. The consistency of these figures across the strata underscores a key point: even babies born only moderately or late preterm, who often escape the most severe neonatal complications, generate a substantial downstream demand on primary care, urgent care and pharmacy services in the first years of life.

The economic burden was equally striking and sharply stratified by gestational age. Mean respiratory-related costs across the whole cohort were $347 per patient per month, standardized to 2023 US dollars, with inpatient care alone accounting for 77.5 percent of that spending, a reminder that readmissions and hospital-based care, not routine visits, drive the financial weight. For very preterm infants the average climbed to $684 per patient per month, more than four times the $164 observed in late preterm infants. Extrapolated across a year, that difference represents thousands of dollars per child and an aggregate cost that scales quickly given how common late preterm birth remains in the United States.

Importantly, these findings were documented in infants who did not carry a bronchopulmonary dysplasia diagnosis, which is precisely why the authors argue the problem is underappreciated. Chronic lung disease of prematurity is the recognized gateway to long-term respiratory follow-up, and infants without that label are often discharged with little structured surveillance. The data suggest that the label itself may miss much of the population at risk, and that respiratory vulnerability after neonatal respiratory distress syndrome is a continuum rather than a diagnosis-specific phenomenon.

The authors conclude that the persistent burden across all gestational ages points to a concrete clinical need: structured long-term respiratory follow-up and preventive strategies that extend beyond the neonatal period, rather than a sharp handoff from intensive care to routine pediatrics. For a condition affecting a large share of the roughly one in ten US infants born preterm each year, the study reframes neonatal respiratory distress syndrome not as an acute problem that resolves with maturing lungs, but as the opening chapter of a respiratory story that families, clinicians and health systems continue to pay for long after the incubator is left behind.

Subject of Research: Long-term respiratory morbidity and healthcare costs in preterm infants with neonatal respiratory distress syndrome after birth hospitalization

Article Title: Long-term clinical and economic outcomes post birth hospitalization in preterm infants with neonatal respiratory distress syndrome: a US real-world retrospective cohort study

Article References: Long-term clinical and economic outcomes post birth hospitalization in preterm infants with neonatal respiratory distress syndrome: a US real-world retrospective cohort study. (n.d.). https://doi.org/10.1186/s12887-026-07822-2

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07822-2

Keywords: neonatal respiratory distress syndrome, preterm infants, bronchopulmonary dysplasia, respiratory morbidity, healthcare resource utilization, health economics, surfactant, CPAP, bronchiolitis, gestational age, retrospective cohort study, neonatology