Along with evidence of a reduction in the risk of any hospitalization, this retrospective cohort study specifically showed a reduction in risk of respiratory tract infection (RTI)-related hospitalization but not on the risk of gastrointestinal (GI) infection-related hospitalization.
Preterm babies are vulnerable to dysbiosis (an imbalance in the gut microbiome) and the negative health outcomes that accompany it. The researchers pointed out that many previous randomized controlled trials (RCTs) and meta-analyses have shown that PS in this group significantly reduced incidence of adverse clinical outcomes such as necrotizing enterocolitis and late-onset sepsis.
PS in preterm infants has therefore become standard practice in many centers across the world, the researchers noted, but the subsequent impact it has on hospitalization in infancy has not previously been investigated.
Study details
This study involved infants born at less than 38 weeks, comparing Epoch 1 (Dec. 1, 2008 to Nov. 30, 2010) when infants did not receive PS to Epoch 2 (June 1, 2012 to May 30, 2014) when they did receive PS. The supplement used was Bifidobacterium Brevi M-16 at a dose of 1.5-3 billion colony-forming units/day.
The primary outcome was any hospitalization, but secondary outcomes were hospitalizations related to RTIs and GI infections because these are the most common causes of hospitalization in infancy and early childhood. A subgroup analysis was also done on extremely preterm infants born at less than 28 weeks.
After excluding those with records missing gestational age and babies who died during neonatal hospitalization, follow-up information was available on 1,238 infants in Epoch 1 and 1,422 in Epoch 2.
The researchers found an 8% reduction in incidence of hospitalization in the two years after birth in Epoch 2, adjusted for gestational age, smoking, socioeconomic status and maternal age, compared with Epoch 1.
The same was not seen for the subgroup of infants born at less than 28 weeks, which had comparable rates of hospitalization in both epochs.
For GI infection-related hospitalizations, there were 40 in Epoch 1 and 50 in Epoch 2—the unadjusted and adjusted risks of GI infection-related hospitalization in Epoch 2 were therefore similar to those in Epoch 1.
For RTI-related hospitalizations, there were 278 in Epoch 1 and 252 in Epoch 2. The unadjusted risk in Epoch 2 was lower compared with Epoch 1, the researchers reported, and a reduction in RTI-related hospitalizations was also observed after adjustment for gestational age, socioeconomic status, maternal age, smoking and ethnicity.
They also noted that a reduction in gestational age by one week increased the risk of hospitalization due to respiratory cause by 6%.
Going forward
“The results of our study provide evidence supporting the hypothesis that the beneficial effects of probiotics may be sustained for up to two years after ceasing the supplementation,” the researchers wrote.
Reflecting on the implications of their findings, they said that the incidence of hospitalizations due to any cause or RT/GI infection-related hospitalization was higher in non-Caucasian ethnicity and so research is needed to specifically assess the efficacy and safety of probiotic supplementation in this high-risk population.
They noted the lack of association between PS and hospitalization for GI infection-related outcomes was contrary to their expectations. Finding no association between PS and hospitalization rates in babies born before 28 weeks was also noted.
"This could be due to the small sample size or a true finding," they wrote. "Further research with a larger sample size is needed to address these findings."
They also address the issue of cessation of PS at discharge. “Evidence is accumulating that gut microbiota influence the structure and function of the brain and other systems through action on the gut-brain axis, gut-lung axis and gut-liver axis. However, meta-analysis of RCTs has shown that PS in the neonatal period does not translate into improved growth or neurodevelopmental outcomes for preterm infants. One possible reason for such a lack of benefit could be the cessation of probiotics prior to discharge from neonatal units.”
The study called for future RCTs in preterm infants to compare the continuation of PS after discharge from neonatal units with stopping intervention at discharge.
Source: Nutrients
doi: 10.3390/nu16132094
“Probiotic Supplementation in the Neonatal Group and the Risk of Hospitalization in the First Two Years: A Data Linkage Study from Western Australia”
Authors: R Srinivasjois et al.