NICU hospital-onset bacteremia linked to increased mortality, risk differs with birth weight

In this Contemporary Pediatrics interview, Erica Prochaska, MD, discussed the study "Hospital-onset bacteremia among neonatal intensive care unit patients," (NICU) which was published in JAMA Pediatrics on June 24, 2024.

Prochaska, co-author of the study, is a pediatric infectious diseases specialist at Johns Hopkins Children's Center and an assistant professor of Pediatrics at the Johns Hopkins University School of Medicine.

According to the study, the Centers for Disease Control and Prevention (CDC) plans to introduce hospital-onset bacteremia (HOB) as a health care-associated infection measure. With unknown epidemiology and clinical characteristics of HOB among infants in the NICU, the study objective was to estimate HOB rate among infants in this setting, measure the association of HOB risk with birth weight group and postnatal age, and estimate HOB-attributable mortality, wrote Prochaska and authors.¹

"We were really interested in looking at multicenter data to better understand how this health care measure would be affecting pediatrics," said Prochaska in the above interview.

"HOB is going to be an electronically extracted health care measure, meaning that the CDC will be able to pull it from the EHR. Currently, the most commonly used bacteremia measure is central line-associated bloodstream infection or CLABSI... CLABSIs have been reduced because of CLABSI bundles and other interventions over the past decade or so, and as a result, the CDC was interested on how can we prevent bacteremia in other ways. Additionally, CLABSIs are very time intensive to adjudicate, and so the goal of HOB is also to take some of the burden off of hospitals from reporting because the CDC would ideally be getting the data themselves, and then risk-adjusting it on their end."

The retrospective, multicenter cohort study from 2016 to 2021 included a convenience sample of 322 NICUs in the United States that featured infants admitted to NICUs for 4 or more days.

"There's been a ton of research in the adult space, on HOB, [but] there's been a lot less in the pediatric space," Prochaska said. "There's been a few studies that are single center, single health system in the NICU, but we were interested in looking at multicenter data to better understand how this health care measure would be affecting pediatrics."

"We basically, within birth weight groups, looked at the first 2 weeks, so it was day 4 to 14 because in the first 3 days, infants wouldn't be eligible for HOB," added Prochaska. "We then compared that early time within bundles of time going forward. What we found is that for infants born less than 1500 grams, their relative risk of HOB went down over the subsequent weeks after the first 2 weeks. The risk was very, very high in the first few weeks for extremely low birth weight and low birth weight infants, but that risk decreased over the subsequent weeks. We found the opposite pattern in infants that were born greater than 1500 grams. We saw they had a relative risk that was higher in the subsequent months as compared to the first few weeks. This shows that the risk changes for infants over time, related to their birth weight and this is very similar to what we've seen in the community setting as well."

According to study results, 13% of the 451,443 included infants were born 1500 grams or less. Among the 9015 HOB events that occurred among 8356 infants (2%) during 8 163 432 days at risk (unadjusted incidence rate, 1.1 per 1000 patient-days; 95% CI, 1.0-1.2), 54.2% occurred in the absence of a central line. Among infants born at 750 grams or less, the HOB rate was 14.2 per 1000 patient-days (95% CI, 12.6-16.1) to 0.4 events per 1000 patient-days among infants born more than 2500 grams (95% CI, 0.4-0.5), within the first 2 weeks after birth.¹

"Among infants born 750 g or less, the relative HOB risk decreased by 90% after day 42 compared with days 4 to 14 (incidence rate ratio [IRR], 0.10; 95% CI, 0.1-0.1)," wrote the investigative team. "Conversely, among infants born more than 2500 g, the relative HOB risk increased by 50% after day 42 compared with days 4 to 14 (IRR, 1.5, 95% CI, 1.2-1.9). Compared with otherwise similar infants without HOB, infants with HOB had an absolute difference in attributable mortality of 5.5% (95% CI, 4.7-6.3)."

"I do hope that these data might be able to help pediatricians give some anticipatory guidance to parents who have just had a emotionally challenging NICU stay," Prochaska said.

"I hope this also provides some solid data that pediatricians can look at and try to reassure parents when they're coming in for that first post-NICU visit. [Telling parents], 'Yes, your child is at high risk for infection, but their infectious risk has gone down dramatically since those first two weeks in the NICU, and we can't say what that necessarily means for them right now in the community, but they're a very different baby than they were at that time.' Hopefully, that is going to be helpful for parents to hear."

Reference:

1. Prochaska EC, Xiao S, Colantuoni E, et al. Hospital-onset bacteremia among neonatal intensive care unit patients. JAMA Pediatr. Published online June 24, 2024. doi:10.1001/jamapediatrics.2024.1840