Neonatal Morbidities and Hospitalization in the First 2 Years of Life Among Infants Born Very Preterm.

IMPORTANCE

Children born very preterm have increased health care use. However, there is a lack of research using contemporary national data quantifying hospitalizations after neonatal discharge to inform counseling of families and health care provision.

OBJECTIVE

To examine hospital admissions after neonatal discharge and before 2 years of age among children born at less than 32 weeks' gestation and assess associations between hospitalization and neonatal morbidities.

DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study used data from all neonatal units and admitting hospitals in England and Wales supplied from the National Neonatal Research Database, linked with the Hospital Episode Statistics Admitted Patient Care database in England and the Patient Episode Database for Wales. Participants were children born at 22 through 31 weeks' gestation from January 1, 2013, to December 31, 2018, who were admitted to neonatal units and discharged home. Analysis was performed from June 26, 2024, to June 3, 2025.

EXPOSURES

Gestational age; sex; small-for-gestational-age status; season at time of neonatal discharge; neonatal morbidities, including bronchopulmonary dysplasia (BPD), severe necrotizing enterocolitis (NEC), and neonatal brain injury; and number of morbidities.

MAIN OUTCOMES AND MEASURES

Prevalence of hospital admission and total calendar days hospitalized across all admissions. Negative binomial regression was used to calculate the adjusted incidence rate ratio (AIRR) for total calendar days hospitalized, adjusting for gestational age, sex, small for gestational age, and season of neonatal discharge.

RESULTS

Among the 39 413 children included (21 360 [54.2%] male; median gestational age at birth, 29 weeks [IQR, 27-31 weeks]), 26 276 (66.7%) did not have major neonatal morbidities. A total of 26 498 children (67.2%) had at least 1 episode of hospitalization between neonatal discharge and the age of 2 years. This ranged from 6138 of 10 444 children born at 31 weeks' gestation (58.8%) to 450 of 517 born at less than 24 weeks (87.0%). The median number of total calendar days hospitalized across admissions increased from 1 day (IQR, 0-5 days) for children born at 31 weeks' gestation to 8 days (IQR, 3-21 days) for those born at less than 24 weeks. Neonatal morbidities were associated with increased total days hospitalized; the AIRR for total hospitalization days for children with vs without BPD was 1.80 (95% CI, 1.72-1.88), for those with vs without severe NEC was 1.88 (95% CI, 1.65-2.15), and for those with vs without neonatal brain injury was 1.46 (95% CI, 1.36-1.57). Combinations of morbidities were associated with total expected days hospitalized: the model estimated that a child born at less than 24 weeks' gestation with 3 morbidities would have 40.6 days (95% CI, 34.8-44.3 days) of hospitalization before age 2 years.

CONCLUSIONS AND RELEVANCE

In this cohort study of children born very preterm discharged from neonatal care in England and Wales, most children experienced hospitalization before their second birthday, and hospitalizations were associated with lower gestational age and neonatal morbidities. These findings can aid counseling and suggest that further research should investigate interventions to prevent hospitalization in this population.