Preterm babies had a higher chance of subsequent childhood hospitalization than those born at term, according to a population-based cohort study.
Infants born extremely early — less than 28 weeks’ gestation — were nearly five times as likely to be admitted to the hospital through age 7-10 than those born at term (adjusted rate ratio 4.92, 95% CI 4.58-5.30), reported Maria Quigley, PhD, of the University of Oxford in England, and colleagues.
Even children born as late as 38 weeks showed a significantly increased risk of later hospitalization (RR 1.19, 95% CI 1.16-1.22), the researchers wrote in The BMJ.
At all ages, hospitalizations were most likely to be caused by infection, but non-infection gastrointestinal and respiratory conditions also led to excess hospital visits.
In an email to MedPage Today, Quigley highlighted the role of infections. “Strategies aimed at the prevention and management of infections [are] important, especially in children born preterm but also in those born a few weeks early.”
Quigley added that it was surprising to see the association between early birth and childhood hospitalization persist until children were 7 to 10 years old — even in kids born at 38 or 39 weeks, though the effect size was smaller. Future research, she stated, should investigate health outcomes associated with gestational age at birth, ideally, on a week-by-week basis.
“The fact that children who were born even a little bit prematurely can have increased risk of hospitalization for up to 10 years, I think that’s something that’s definitely worth highlighting,” said David Hackney, MD, a maternal-fetal medicine specialist at University Hospitals in Cleveland.
Hackney, who was not involved with this research, said it brings attention to the long-term effects and ongoing harm of preterm delivery. “[Preterm birth] is one of the major public health issues of our time that doesn’t always get the attention that it needs, relative to the morbidity and mortality associated with it,” he said in an interview.
But while the investigators observed an increased risk in babies born just a week early, the effect sizes are small, he added, and clinical implications for babies born just before term are not clear from these findings.
Preterm birth is a risk factor for illnesses such as respiratory disease, infections, and neurodevelopmental deficits. Quigley’s group aimed to evaluate the long-term effects of prematurity and whether the risk of illness and hospitalization declined in later childhood.
The researchers investigated the relationship between early birth and childhood hospitalization through the TIGAR study, a population-based record linkage study in England that tracks birth and hospital admissions during childhood. They included all live, singleton births during 2005-2006 — more than 1 million in all — and followed children until 2015. Those born before 23 weeks or after 42 weeks were not included.
Quigley’s group measured total inpatient hospital admissions during childhood, which were reported during five different time periods starting when children were younger than 1 and continuing through age 7-10. Analyses included adjustment for confounders including maternal age at delivery, marital status, race and ethnicity, socioeconomic status, mode of delivery, sex, birth month, and small for gestational age.
Half of children in the study were hospitalized at least once. Around 60% of all admissions were emergencies. Kids admitted to the hospital were more likely to be born to mothers who were unmarried, younger, born in Britain, and of lower socioeconomic status. Hospital admission was also associated with C-section birth (as has been seen in previous studies).
During infancy, rates of hospitalization in babies born at less than 28 weeks was sixfold higher than in those born at term (RR 6.34, 95% CI 5.80-6.85), and among babies born at 39 weeks it was 10% higher (RR 1.10, 95% CI 1.08-1.11). By age 10, however, these risk ratios dropped to 3.28 (95% CI 2.82-3.82) and 1.06 (95% CI 1.03-1.08), respectively.
Among babies born extremely preterm, the most common cause of admission at age 7-10 was central nervous system conditions such as cerebral palsy and epilepsy.
Quigley and colleagues noted that data used to assess hospitalizations was used primarily for financial reimbursement, not research, so the quality is inconsistent. Also, kids who left the country could not be included in the analysis.
Disclosures
The TIGAR study was funded by the Medical Research Council.
Quigley and co-authors reported no relevant relationships with industry.