Epidemiology and trends of necrotizing enterocolitis in Sweden: 1987-2009

Risk factor analysis and nomogram prediction model construction for NEC complicated by intestinal perforation

OBJECTIVE

To investigate the clinical characteristics of neonatal necrotizing enterocolitis (NEC) complicated by intestinal perforation and predict the incidence of intestinal perforation in NEC.

METHODS

Neonates diagnosed with NEC at the Affiliated Hospital of Zunyi Medical University from January 2012 to May 2022 were enrolled, and the clinical data were collected and analyzed retrospectively. The patients were divided into two groups based on intestinal perforation occurrence or not. Mann-Whitney U tests, t-tests, chi-square tests, and fisher's exact tests were performed between-group comparisons. Logistic and lasso regressions were applied to screen independent risk factors for concomitant bowel perforation, and R software (RMS package) was used to formulate the nomogram prediction model. In addition, the receiver operating curve (ROC) and the calibration curve were drawn to verify the predictive power, while decision curve analysis (DCA) was constructed to evaluate the clinical applicability of the nomogram model.

RESULTS

One hundred eighty neonates with NEC were included, of which 48 had intestinal perforations, and 132 did not; the overall incidence of intestinal perforation was 26.67% (48/180). Bloody stool (OR = 5.60), APTT ≥ 50 s (OR = 3.22), thrombocytopenia (OR = 4.74), and hypoalbuminemia (OR = 5.56) were identified as independent risk variables for NEC intestinal perforation (P < 0.05) through multivariate logistic regression analysis. These factors were then applied to develop a nomogram prediction model (C-index = 0.838) by using the R software. The area under the curve (AUC) for the nomogram in the training and validation cohorts were 0.838 (95% Cl: 0.768, 0.908) and 0.802 (95% CI: 0.659, 0.944), respectively. The calibration curve shown that the nomogram has a good predictive ability for predicting the risk of intestinal perforation occurrence. And the decision curve and clinical impact curve analyses demonstrated good clinical utility of the nomogram model.

CONCLUSION

We found that Bloody stool, APTT ≥ 50 s, Thrombocytopenia, and hypoalbuminemia could be used as independent risk factors for predicting intestinal perforation in neonates with NEC. The nomogram model based on these variables had high predictive values to identify NEC patients with intestinal perforation.

Factors associated with the increased incidence of necrotising enterocolitis in extremely preterm infants in Sweden between two population-based national cohorts (2004-2007 vs 2014-2016)

OBJECTIVE

To investigate potential risk factors behind the increased incidence of necrotising enterocolitis (NEC) in Swedish extremely preterm infants.

DESIGN

Registry data from two population-based national cohorts were studied. NEC diagnoses (Bell stage ≥II) were validated against hospital records.

PATIENTS

All liveborn infants <27 weeks of gestation 2004-2007 (n=704) and 2014-2016 (n=895) in Sweden.

MAIN OUTCOME MEASURES

NEC incidence.

RESULTS

The validation process resulted in a 28% reduction of NEC cases but still confirmed a higher NEC incidence in the later epoch compared with the earlier (73/895 (8.2%) vs 27/704 (3.8%), p=0.001), while the composite of NEC or death was lower (244/895 (27.3%) vs 229/704 (32.5%), p=0.022). In a multivariable Cox regression model, censored for mortality, there was no significant difference in early NEC (0-7 days of life) between epochs (HR=0.9 (95% CI 0.5 to 1.9), p=0.9), but being born in the later epoch remained an independent risk factor for late NEC (>7 days) (HR=2.7 (95% CI 1.5 to 5.0), p=0.001). In propensity score analysis, a significant epoch difference in NEC incidence (12% vs 2.8%, p<0.001) was observed only in the tertile of infants at highest risk of NEC, where the 28-day mortality was lower in the later epoch (35% vs 50%, p=0.001). More NEC cases were diagnosed with intramural gas in the later epoch (33/73 (45.2%) vs 6/26 (23.1%), p=0.047).

CONCLUSIONS

The increase in NEC incidence between epochs was limited to cases occurring after 7 days of life and was partly explained by increased survival in the most extremely preterm infants. Misclassification of NEC is common.

Risk factors associated with necrotizing enterocolitis in preterm infants: A case-control study

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common life-threatening gastrointestinal emergency in prematurity. The pathophysiology is multifactorial and remains incompletely understood. Early diagnosis and treatment could reduce the risk of mortality and morbidity. We aimed to identify factors associated with NEC in preterm newborns.

METHOD

This case-control study included all preterm newborns presenting with NEC and managed between January 1, 2009 and December 31, 2018 in the neonatal intensive care unit of Nancy. For each case, two controls were matched according to three criteria: gestational age (WG), date of birth, and mode of delivery. Antenatal, peripartum, and postnatal risk factors prior to NEC were analyzed.

RESULTS

A total of 292 infants were involved in the study, 113 of whom had NEC. Mean gestational age for newborns with NEC was 29 WG, and mean birth weight, 1340 g. Only early-onset infection was identified as a significant risk factor for NEC (15% vs. 6.6% for infection p<0.04, and 28.3% vs. 16.4% p<0.02 for infection and sepsis, NEC vs. controls, respectively). Late-onset feeding and initial continuous enteral feeding were significantly associated with the occurrence of more severe NEC (p<0.02 and p = 0.03, respectively).

CONCLUSION

The results of this study are consistent with intestinal dysbiosis being a risk factor for NEC. Early-onset infection was found to be a significant risk factor. Enteral feeding practice may also be associated with NEC.

Association of anemia and platelet activation with necrotizing enterocolitis with or without sepsis among low birth weight neonates: a case-control study

Background

This study aims to evaluate the value of the proportion of large platelets (PLCR) and platelet crit (PCT) in predicting necrotizing enterocolitis (NEC) in low birth weight (LBW) neonates.

Methods

A total of 155 LBW (<2,500 g) neonates with NEC, who were admitted to the neonatal intensive care unit (NICU) of the hospital from January 1, 2017, to November 30, 2019, were included in the case group. According to the 1:3 case-control study design, a total of 465 LBW neonates without NEC (three for each LBW neonate with NEC), who were admitted to the NICU and born ≤24 h before or after the birth of the subjects, were included in the control group.

Results

During the study period, a total of 6,946 LBW neonates were born, of which 155 had NEC, including 92 who also had sepsis. Neonatal sepsis was the most important risk factor and confounding factor for NEC in LBW neonates. Further stratified analysis showed that in LBW neonates without sepsis, anemia [P = 0.001, odds ratio (OR) = 4.367, 95% confidence interval (CI): 1.853-10.291], high PLCR (P < 0.001, OR = 2.222, 95% CI: 1.633-3.023), and high PCT (P = 0.024, OR = 1.368, 95% CI: 1.042-1.795) increased the risk of NEC and the receiver operating characteristic curve area of PLCR, sensitivity, specificity, and cutoff value were 0.739, 0.770, 0.610, and 33.55, respectively.

Conclusions

The results showed that 2/100 LBW neonates were at risk for NEC, and the stratified analysis of the confounding factors of sepsis identified the risk factors of NEC in LBW neonates. This study first reported the significance of PLCR in the early prediction of NEC occurrence in LBW neonates without sepsis.

Body composition and bone mass among 5-year-old survivors of necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) affects the intestine of preterm infants. Preterm infants risk inadequate bone mineralization. This risk may increase if the intestinal uptake of minerals is affected after NEC.

METHODS

This is a study of growth, bone mineral density (BMD), bone mineral content (BMC), and body composition at 5 years of age among Swedish children born before gestational week 37 + 0 with a history of NEC, minimum stage IIA, compared to matched controls. Fifty children, 25 NEC cases and 25 controls, were examined with dual energy X-ray absorptiometry (DXA) and DXA with laser.

RESULTS

The NEC cases had lower weight, -1.3 SDS vs -0.7 SDS, a lower fat mass and fat percent, 23.4 vs 29.1%, compared to the controls. NEC cases had lower BMC total body head excluded, 355.6 g vs 416.7 g. BMD Z-scores were lower among NEC cases in total body head excluded, -0.7 vs -0.1, and in lumbar spine.

CONCLUSIONS

Preterm NEC survivors at 5 years of age had reduced growth, an altered body composition, and indications of a lower bone mass compared to matched controls. The study suggests that preterm infants diagnosed with NEC need special attention during childhood regarding growth and bone health.

IMPACT

A follow-up longitudinal study of growth, bone health, and body composition at 5 years of age among children born preterm with a history of NEC compared to matched controls. The NEC cases had lower weight than controls. NEC cases had an altered body composition with lower fat mass compared to controls. The DXA results showed that the NEC cases had lower bone mineral content and a tendency to lower bone mineral density. The study suggests that preterm infants diagnosed with NEC need special attention at follow-up regarding growth and bone health compared to preterm infants without NEC.

Screening inflammatory protein biomarkers on premature infants with necrotizing enterocolitis

OBJECTIVE

This study aimed to explore potential inflammatory biomarkers for early prediction of necrotizing enterocolitis (NEC) in premature infants.

METHODS

Plasma samples were collected from premature infants with NEC (n = 30), sepsis (n = 29), and controls without infection (n = 29). The 92 inflammatory-related proteins were assessed via high-throughput OLINK proteomics platform.

RESULTS

There were 11 inflammatory proteins that significate differences (p < 0.05) among NEC, sepsis and control preterm infants, which include IL-8, TRAIL, IL-24, MMP-10, CCL20, CXCL1, OPG, TSLP, MCP-4, TNFSF14 and LIF. A combination of these 11 proteins could serve as differential diagnosis between NEC and control infants (AUC = 0.972), or between NEC and sepsis infants (AUC = 0.881). Furthermore, the combination of IL-8, OPG, MCP-4, IL-24, LIF and CCL20 could distinguish Stage II and III of NEC (AUC = 0.977). Further analysis showed the combination of IL-8, IL-24 and CCL20 have the best prediction value for NEC and control (AUC = 0.947), NEC and sepsis (AUC = 0.838) and different severity of NEC (AUC = 0.842).

CONCLUSION

Inflammatory proteins were different expressed in premature infants with NEC compared with controls or sepsis. Combining these proteins provide a higher diagnostic potential for preterm NEC infants.

Machine learning-based risk factor analysis of necrotizing enterocolitis in very low birth weight infants

This study used machine learning and a national prospective cohort registry database to analyze the major risk factors of necrotizing enterocolitis (NEC) in very low birth weight (VLBW) infants, including environmental factors. The data consisted of 10,353 VLBW infants from the Korean Neonatal Network database from January 2013 to December 2017. The dependent variable was NEC. Seventy-four predictors, including ambient temperature and particulate matter, were included. An artificial neural network, decision tree, logistic regression, naïve Bayes, random forest, and support vector machine were used to evaluate the major predictors of NEC. Among the six prediction models, logistic regression and random forest had the best performance (accuracy: 0.93 and 0.93, area under the receiver-operating-characteristic curve: 0.73 and 0.72, respectively). According to random forest variable importance, major predictors of NEC were birth weight, birth weight Z-score, maternal age, gestational age, average birth year temperature, birth year, minimum birth year temperature, maximum birth year temperature, sepsis, and male sex. To the best of our knowledge, the performance of random forest in this study was among the highest in this line of research. NEC is strongly associated with ambient birth year temperature, as well as maternal and neonatal predictors.

Necrotising enterocolitis, late-onset sepsis and mortality after routine probiotic introduction in the UK

OBJECTIVE

To compare necrotising enterocolitis (NEC), late-onset sepsis (LOS), focal intestinal perforation (FIP) and mortality in infants from a single neonatal unit before and after probiotic introduction.

DESIGN

Retrospective review of infants <32 weeks admitted January 2009-December 2012 (no probiotic) and January 2013-December 2017 (routine probiotics). Infants included were admitted before day 3, and not transferred out before day 3. NEC, LOS and FIP were defined with standard definitions.

PATIENTS

1061 infants were included, 509 preprobiotic and 552 postprobiotic. Median gestation, birth weight and antenatal steroid use did not differ, and proportions of extremely low birthweight infants were similar (37% and 41%).

RESULTS

Overall unadjusted risk of NEC (9.2% (95% CI 7.1 to 12.1) vs 10.6% (95% CI 8.2 to 13.4), p=0.48), LOS (16.3% (95% CI 13.2 to 19.6) vs 14.1% (95% CI 11.5 to 17.4), p=0.37) and mortality (9.2% (95% CI 7.1 to 12.1) vs 9.7% (95% CI 7.6 to 12.6), p=0.76) did not differ, nor proportion of surgical NEC. In multiple logistic regression, accounting for gestation, birth weight, antenatal steroid, maternal milk, chorioamnionitis and sex, probiotic receipt was not significantly associated with NEC (adjusted OR (aOR) 1.08 (95% CI 0.71 to 1.68), p=0.73), LOS or mortality. In subgroup (645 infants) >28 weeks, aOR for NEC in the probiotic cohort was 0.42 (95% CI 0.2 to 0.99, p=0.047). FIP was more common in the probiotic cohort (OR 2.3 (95% CI 1.0 to 5.4), p=0.04), not significant in regression analysis (2.11 (95% CI 0.97 to 4.95), p=0.05).

CONCLUSIONS

Probiotic use in this centre did not reduce overall mortality or rates of NEC, LOS or FIP but subgroup analysis identified NEC risk reduction in infants >28 weeks, and LOS reduction <28 weeks.

Initial surgical treatment of necrotizing enterocolitis: a meta-analysis of peritoneal drainage versus laparotomy

Necrotizing enterocolitis (NEC) in premature infants is associated with high morbidity and mortality, and the optimal intervention remains uncertain. To compare the mortality of primary peritoneal drainage versus primary peritoneal laparotomy as initial surgical intervention for NEC. All data were extracted from PubMed, Embase, and the Cochrane Library. Studies published up to December 2021. Patients with NEC. Studies centered on primary peritoneal drainage and primary peritoneal laparotomy as the initial surgical treatment. Mortality outcomes were available for both interventions. Randomized controlled trials, retrospective cohort studies, and case series in peer-reviewed journals. Language limited to English. Odds ratio (OR) with 95% confidence intervals (CIs) was used to evaluate mortality outcome. Subgroup analyses and linear regression were performed to ascertain the association between mortality pre-specified factors. Data of 1062 patients received peritoneal drainage and 2185 patients received peritoneal laparotomy from five case series, five retrospective cohort studies, and three randomized controlled trials. Peritoneal drainage caused similar mortality (OR 1.49, 95% CI 0.99-2.26) compared with peritoneal laparotomy as initial surgical management for NEC infants. The subgroup analysis of study design, sample size, birth weight, and sex showed similar findings, but inconsistent results were found for country (USA: 1.47, 95% CI 0.90-2.41; Canada: 2.53, 95% CI 0.30-21.48; Australia: 10.29, 95% CI 1.03-102.75; Turkey: 0.09, 95% CI 0.01-0.63) and gestational age (age mean difference < 3: 1.23, 95% CI 0.72-2.11; age mean difference ≥ 3: 2.29, 95% CI 1.04-5.05). No statistically significance was found for the linear regression between mortality and sample size (P = 0.842), gestational age (P = 0.287), birth weight (P = 0.257), sex (P = 0.6). Small sample size, high heterogeneity, NEC, and spontaneous intestinal perforation (SIP) had to be analyzed together, lack of selection criteria for the future selection of an intervention, and no clear, standardized procedures.   Conclusion: There was no significant difference in mortality between peritoneal drainage and laparotomy as initial surgical intervention. The results suggest that either intervention could be used in selected patients. What is Known: • Necrotizing enterocolitis (NEC) in premature infants is associated with high morbidity and mortality, and the optimal intervention remains uncertain. What is New: • No significant difference of mortality between peritoneal drainage and laparotomy as initial surgical intervention.

Amino acid infusions in umbilical artery catheters enhance protein administration in infants born at extremely low gestational age

AIM

It is challenging to provide extremely low gestational age neonates (ELGANs) with adequate protein supply. This study aimed to investigate whether amino acid (AA) infusion in the umbilical artery catheter (UAC) in ELGANs is safe and enhances protein supply and growth.

METHOD

A before and after study including infants born <27 weeks, treated in Uppsala, Sweden, during 2004-2007, compared those receiving normal saline/10% dextrose in water with those receiving AA infusion in the UAC. Data were retrieved from the Extremely Preterm Infants in Sweden Study, hospital records and the Swedish Neonatal Quality Register. Group comparisons, univariate and multivariate analyses were conducted.

RESULTS

AA group (n = 41, females 39%) received on average approximately 0.3 g/kg/day more protein during the first postnatal week, compared to control group (n = 30, females 40%) (unstandardised coefficient (B) 0.26, p .001) but no difference was noted during 8-28 postnatal days. The type of infusion was not associated with growth variables. The incidence of neonatal morbidities and UAC-related thrombosis did not differ between the groups.

CONCLUSION

AA infusions in the UACs in ELGANs is safe and enhances protein supply during the first postnatal week. However, this practice is not associated with growth during the first 28 postnatal days.

Epidemiology of necrotizing enterocolitis in preterm infants in China: A multicenter cohort study from 2015 to 2018

PURPOSE

To describe the current incidence, case-fatality rate and surgical treatment proportion of necrotizing enterocolitis (NEC) among preterm infants in China.

METHODS

The study included all live neonates with <34 weeks gestational age (GA) admitted to 25 tertiary hospitals within 7 days of birth from 19 provinces in China between May 2015 and April 2018. NEC was defined as ≥stage II according to Bell's criteria.

RESULTS

A total of 24,731 infants were included. The overall incidence of NEC was 3.3% and decreased with increasing GA and birth weight. The incidence of NEC was 4.8% in very preterm infants and 1.8% in infants born ≥32 weeks GA, respectively. The overall case-fatality rate of NEC was 9.5%, and the case-fatality rate was 7.0% among infants born ≥32 weeks GA. A total of 214 (27.9%) infants underwent surgery, and their overall case-fatality rate was 13.6%. Significant variation in the incidence of NEC existed among different centers (0.6-11.1%).

CONCLUSIONS

The incidence and case-fatality rate of NEC are high in China, especially among infants with GA ≥32 weeks, and varies significantly among sites. A high proportion of NEC infants required surgical management, with an even higher case-fatality rate.

Antibiotics in the medical and surgical treatment of necrotizing enterocolitis. A systematic review

BACKGROUND

The aim of this review was to identify relevant randomized controlled trials (RCTs) and non-RCTs to evaluate the existing knowledge on the effect of antibiotic treatment for infants with necrotizing enterocolitis (NEC).

OBJECTIVE

Identifying 1) the best antibiotic regimen to avoid disease progression as assessed by surgery or death, 2) the best antibiotic regimen for infants operated for NEC as assessed by re-operation or death.

METHODS

Embase, MEDLINE and Cochrane were searched systematically for human studies using antibiotics for patients with NEC, Bell's stage II and III.

RESULTS

Five studies were included, with a total of 375 infants. There were 2 RCT and 3 cohort studies. Four main antibiotic regimens appeared. Three with a combination of ampicillin + gentamycin (or similar) with an addition of 1) clindamycin 2) metronidazole or 3) enteral administration of gentamycin. One studied investigated cefotaxime + vancomycin. None of the included studies had a specific regimen for infants undergoing surgery.

CONCLUSIONS

No sufficient evidence was found for any recommendation on the choice of antibiotics, the route of administration or the duration in infants treated for NEC with Bell's stage II and III.

Hyponatremia at the onset of necrotizing enterocolitis is associated with intestinal surgery and higher mortality

It has previously been shown that hyponatremia reflects the severity of inflammation in pediatric gastrointestinal diseases. Interpretation of electrolyte disorders is a common, but not well studied challenge in neonatology, especially in the context of early detection of necrotizing enterocolitis and bowel necrosis. The aim of this study was to assess if hyponatremia, or a decrease in plasma sodium level, at the onset of necrotizing enterocolitis (NEC) is associated with intestinal ischemia/necrosis requiring bowel resection and/or NEC-related deaths. This was a retrospective cohort study including patients with verified NEC (Bell's stage ≥ 2) during the period 2009-2014. Data on plasma sodium 1-3 days before and at the onset of NEC were collected. The exposure was hyponatremia, defined as plasma sodium < 135 mmol/L and a decrease in plasma sodium. Primary outcome was severe NEC, defined as need for intestinal resection due to intestinal ischemia/necrosis and/or NEC-related death within 2 weeks of the onset of NEC. Generalized linear models were applied to analyze the primary outcome and presented as odds ratio. A total of 88 patients with verified NEC were included. Fifty-four (60%) of them had severe NEC. Hyponatremia and a decrease in plasma sodium at onset of NEC were associated with increased odds of severe NEC (OR crude 3.91, 95% CI (1.52-10.04) and 1.19, 95% CI (1.07-1.33), respectively). Also, a sub-analysis, excluding infants with pneumoperitoneum during the NEC episode, showed an increased odds ratio for severe NEC in infants with hyponatremia (OR 23.0, 95% CI (2.78-190.08)).

CONCLUSIONS

The findings of hyponatremia and/or a sudden decrease in plasma sodium at the onset of NEC are associated with intestinal surgery or death within 2 weeks.

WHAT IS KNOWN

• Clinical deterioration, despite optimal medical treatment, is a relative indication for surgery in infants with necrotizing enterocolitis. • Hyponatremia is a common condition in preterm infants from the second week of life.

WHAT IS NEW

• Hyponatremia and a decrease in plasma sodium level at the onset of necrotizing enterocolitis are positively associated with need of surgery or death within 2 weeks. • In infants with necrotizing enterocolitis, without pneumoperitoneum, where clinical deterioration despite optimal medical treatment is the only indication for surgery, hyponatremia, or a decrease in plasma sodium level can predict the severity of the disease.

Effects of Probiotics and Lactoferrin on Necrotizing Enterocolitis in Preterm Infants

Background

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in neonates. Despite intensive research, the etiology and pathophysiology of NEC is still obscure. Evidence from recent studies and meta-analyses showed a significant role of probiotics as a prophylactic measure in reducing NEC, sepsis, and mortality. However, obstacles against the generalization of the results still remain. The aim of the study was to evaluate the role of prophylactic administration of probiotics and lactoferrin in reducing the rate of NEC in preterm infants.

Methods

In this retrospective cohort study, all medical records of infants born with a birth weight of 1,500 g and less who were born between 2012 and 2017 were reviewed. The enrolled infants were divided into two groups: group 1 included infants born between January 2012 and August 2014, a period before probiotics were started in our unit, and group 2 included infants born between January 2014 and December 2017 after starting probiotics and lactoferrin. Multiple variables were collected including maternal data, neonatal data, and risk factors for NEC.

Results

Medical records of 284 infants who met our inclusion criteria were reviewed. Of the 284 infants, 134 were in group 1 and 150 infants were in group 2. There were no significant statistical differences between group 1 and group 2 in neonatal and maternal demographic data and clinical data. Of 134 infants who received probiotics and lactoferrin, 11 developed NEC, while 26 of the 150 infants in group 2 developed NEC, and the difference was statistically significant (p = 0.023).

Conclusion

Probiotics and lactoferrin given orally to very low birth weight preterm infants were associated with a decreased rate of NEC.

Incidence of necrotizing enterocolitis in South Korea from 2007 to 2017

OBJECTIVES

The aim of this study was to investigate the trends of the incidence of and mortality from necrotizing enterocolitis (NEC) in South Korea.

METHODS

Claim data were extracted with diagnosis code, including all stage of NEC. Kaplan-Meier curves for cumulative mortality rates are presented by birth weight (Bwt) and gestational age (GA).

RESULT

The total number of NEC cases was 5840. The ratio of males to females was 1.2:1. There were 11.9 cases per 10,000 births. There were approximately 10 cases per 1000 preterm births and 50 per 1000 very preterm births. The mortality of patients born under 37 weeks decreased from 38.7% in 2007 to 20.9% in 2017. Male sex, lower GA, and lower Bwt were risk factors for mortality.

CONCLUSIONS

NEC incidence and mortality have been decreasing over time in South Korea. Male sex, lower GA, and Bwt were risk factors for mortality.

Temporal and seasonal variations in incidence of stage II and III NEC-a 28-year epidemiologic study from tertiary NICUs in Connecticut, USA

OBJECTIVE

To investigate seasonality and temporal trends in the incidence of NEC.

STUDY DESIGN

A retrospective cohort study from two tertiary NICUs in northern and central Connecticut involving 16,761 infants admitted over a 28-year period. Various perinatal and neonatal risk factors were evaluated by univariate, multivariate, and spectral density analyses.

RESULTS

Incidence of NEC was unchanged over the 28 years of study. Gestational age, birth weight, and birth-months (birth in April/May) were independently associated with stage II or III NEC even after adjusting for confounding factors (p < 0.05). Yearly NEC incidence showed a multi-modal distribution with spectral density spikes approximately every 10 years.

CONCLUSION(S)

Temporal and seasonal factors may play a role in NEC with a peak incidence in infants born in April/May and periodicity spikes approximately every 10 years. These trends suggest non-random and possibly environmental factors influencing NEC.

Sialylated human milk oligosaccharides prevent intestinal inflammation by inhibiting toll like receptor 4/NLRP3 inflammasome pathway in necrotizing enterocolitis rats

Background

Necrotizing enterocolitis (NEC) remains a fatal gastrointestinal disorder in neonates and has very limited therapeutic options. Sialylated human milk oligosaccharides (SHMOs) improve pathological changes in experimental NEC models. The objectives of this study were to investigate the involvement of NLRP3 inflammasome in NEC pathology and to explore the effects of SHMOs on toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB)/NLRP3 inflammatory pathway in experimental NEC.

Methods

The intestinal-tissue segments were collected from NEC infants, NLRP3 and caspase-1 positive cell were examined by immunohistochemistry. Newborn rats were hand-fed with formula containing or non-containing SHMOs (1500 mg/L) and exposed to hypoxia/cold stress to induce experimental NEC. The NEC pathological scores were evaluated; ileum protein expression of membrane TLR4 (mTLR4), inhibitor κB-α (IκB-α), NF-κB p65 subunit and phospho-NF-κB p65, as well as NLRP3 and caspase-1 were analyzed; ileum concentrations of interleukin-1β, interleukin-6, tumor necrosis factor-α (TNF-α) were also measured. Human colon epithelial Caco-2 cells were pre-treated with or without SHMOs and stimulated with TLR4 activator, lipopolysaccharide. Cell viabilities, mitochondrial membrane potential and supernatant matrix metalloprotease 2 (MMP-2) activities were analyzed.

Results

Increased frequencies of NLRP3 and caspase-1 positive cells were found in the lamina propria of damaged intestinal area of NEC neonates. SHMOs supplementation reduced NEC incidence and pathological damage scores of rats challenged with hypoxia/cold stress. Accumulation of interleukin-1β, interleukin-6 and TNF-α in NEC group were attenuated in SHMOs + NEC group. Protein expression of mTLR4, NLRP3 and caspase-1 were elevated, cytoplasmic IκB-α were reduced, nuclear phospho-NF-κB p65 were increased in the ileum of NEC rats. SHMOs supplementation ameliorated the elevation of mTLR4, NLRP3 and caspase-1, restored IκB-α in the cytoplasmic fraction and reduced phospho-NF-κB p65 in the nuclear fraction in the ileum of NEC rats. SHMOs pre-treatment improved Caco-2 cell viability, mitigated loss of mitochondrial membrane potential and modulated MMP-2 activities in the presence of lipopolysaccharide in-vitro.

Conclusions

This study provided clinical evidence of involvement of NLRP3 inflammasome in NEC pathology, and demonstrated the protective actions of SHMOs might be owing to the suppression of TLR4/NF-κB/NLRP3-mediated inflammation in NEC.

Hydrogen Promotes the M1 Macrophage Conversion During the Polarization of Macrophages in Necrotizing Enterocolitis

Background: Hydrogen is protective against intestinal injury in necrotizing enterocolitis (NEC), mainly through to alleviate inflammation response. The M1 macrophages can promote inflammation. We hypothesized that hydrogen would promote the M1 macrophages conversion during the polarization and reduce the inflammatory factors in NEC. Methods: We used M1 and M2 macrophages induced from RAW264.7 cells and bone marrow-derived macrophages, models of NEC and macrophages derived from spleens, abdominal lymph nodes and lamina propria in model mice. Cytokines, CD16/32 and CD206 were measured by quantitative PCR, flow cytometry. Nuclear factor-κB (NF-κB) p65 were determined by western blot. Histology staining were used to assess the severity of NEC. Results: Macrophages were successfully polarized to M1 or M2 by assessing the expression of inflammatory factors. Pro-inflammatory factors and CD16/32 in M1 macrophages were decreased, and the expression of CD16/32 in lamina propria were inhibited after treatment with hydrogen, but the changes has no effects in other tissues. Hydrogen inhibited the NF-κB p65 in M1 macrophages nucleus and distal ileum of NEC. HE staining showed hydrogen could attenuate the severity of NEC. Conclusion: Hydrogen could attenuate the severity of NEC through promoting M1 macrophages conversion by inhibited the expression of NF-κB p65 in the nucleus.

Interleukin 8 may predict surgical necrotizing enterocolitis in infants born less than 1500 g

Necrotizing enterocolitis (NEC) often leads to gastrointestinal emergency resulting high mortality in very low birth weight infants (VLBWIs) requiring surgery. To date, few studies have explored the role of serum cytokines in the development of feeding intolerance (FI) or NEC outcomes in VLBWIs. Infants born weighing <1500 g or of 32 weeks of gestational age were prospectively enrolled from May 2018 to Dec 2019. We measured several cytokines routinely within 72 h of life, even before NEC-like symptoms developed. NEC or FI group comprised 17 (27.4%) infants, and 6 (9.7%) infants had surgical NEC. The gestational age and birth weight were significantly lower in the NEC or FI group with more prematurity-related complications. The surgical NEC group also demonstrated significantly lower gestational age and birth weight along with more infants experiencing refractory hypotension within a 1 week of life, pulmonary hypertension, and patent ductus arteriosus. IL-10 levels were significantly higher in the NEC or FI group, whereas IL-8 levels were significantly higher in the infants with surgical NEC. Our findings indicated to IL-8 can predict surgical NEC while increased IL-10 can predict NEC development in VLBWIs.

Faecal volatile organic compounds in preterm babies at risk of necrotising enterocolitis: the DOVE study

BACKGROUND

Early diagnosis of necrotising enterocolitis (NEC) may improve prognosis but there are no proven biomarkers.

OBJECTIVE

To investigate changes in faecal volatile organic compounds (VOCs) as potential biomarkers for NEC.

DESIGN

Multicentre prospective study.

SETTINGS

8 UK neonatal units.

PATIENTS

Preterm infants <34 weeks gestation.

METHODS

Daily faecal samples were collected prospectively from 1326 babies of whom 49 subsequently developed definite NEC. Faecal samples from 32 NEC cases were compared with samples from frequency-matched controls without NEC. Headspace, solid phase microextraction gas chromatography/mass spectrometry was performed and VOCs identified from reference libraries. VOC samples from cases and controls were compared using both discriminant and factor analysis methods.

RESULTS

VOCs were found to cluster into nine groups (factors), three were associated with NEC and indicated the possibility of disease up to 3-4 days before the clinical diagnosis was established. For one factor, a 1 SD increase increased the odds of developing NEC by 1.6 times; a similar decrease of the two other factors was associated with a reduced risk (OR 0.5 or 0.7, respectively). Discriminant analyses identified five individual VOCs, which are associated with NEC in babies at risk, each with an area under the receiver operating characteristics curve of 0.75-0.76, up to 4 days before the clinical diagnosis was made.

CONCLUSIONS

Faecal VOCs are altered in preterm infants with NEC. These data are currently insufficient to enable reliable cotside detection of babies at risk of developing NEC and further work is needed investigate the role of VOCs in clarifying the aetiology of NEC.

Global incidence of Necrotizing Enterocolitis: a systematic review and Meta-analysis

BACKGROUND

Necrotizing Enterocolitis (NEC) is a major cause of morbidity and mortality in the Neonatal Intensive Care Unit (NICU), yet the global incidence of NEC has not been systematically evaluated. We conducted a systematic review and meta-analysis of cohort studies reporting the incidence of NEC in infants with Very Low Birth Weight (VLBW).

METHODS

The databases searched included PubMed, MEDLINE, the Cochrane Library, EMBASE and grey literature. Eligible studies were cohort or population-based studies of newborns including registry data reporting incidence of NEC. Incidence were pooled using Random Effect Models (REM), in the presence of substantial heterogeneity. Additional, bias adjusted Quality Effect Models (QEM) were used to get sensitivity estimates. Subgroup analysis and meta-regression were used to explore the sources of heterogeneity. Funnel plots as appropriate for ratio measures were used to assess publication bias.

RESULTS

A systematic and comprehensive search of databases identified 27 cohort studies reporting the incidence of NEC. The number of neonate included in these studies was 574,692. Of this 39,965 developed NEC. There were substantial heterogeneity between studies (I2 = 100%). The pooled estimate of NEC based on REM was 7.0% (95% CI: 6.0-8.0%). QEM based estimate (6.0%; 95% CI: 4.0-9.0%) were also similar. Funnel plots showed no evidence of publication bias. Although, NEC estimates are similar across various regions, some variation between high and low income countries were noted. Meta regression findings showed a statistically significant increase of NEC over time, quantified by the publication year.

CONCLUSION

Seven out of 100 of all VLBW infants in NICU are likely to develop NEC. However, there were considerable heterogeneity between studies. High quality studies assessing incidence of NEC along with associated risk factors are warranted.

Trends in incidence and outcomes of necrotizing enterocolitis over the last 12 years: A multicenter cohort analysis

OBJECTIVE

We sought to describe changes in the incidence and mortality of necrotizing enterocolitis (NEC) and associated surgical management strategies for very low birth weight (VLBW) infants.

METHODS

Data were prospectively collected on VLBW infants (≤1500 g or < 29 weeks) born 2006 to 2017 and admitted to 820 U.S. centers. NEC was defined by the presence of at least one clinical and one radiographic finding. Trends analyses were performed to assess changes in incidence and mortality over time.

RESULTS

Of 473,895 VLBW infants, 36,130 (7.6%) were diagnosed with NEC, of which 21,051 (58.3%) had medical NEC and 15,079 (41.7%) had surgical NEC. Medical NEC decreased from 5.3% to 3.0% (p < 0.0001). Surgical NEC decreased from 3.4% to 3.1% (p = 0.06). Medical NEC mortality decreased from 20.7% to 16.8% (p = 0.003), while surgical NEC mortality decreased from 36.6% to 31.6% (p < 0.0001). In the surgical cohort, the use of primary peritoneal drainage (PPD) versus initial laparotomy rose from 23.2% to 46.8%.

CONCLUSION

The incidence and mortality of both medical and surgical NEC have decreased over time. Changes in surgical management during this time period included the increased utilization of primary peritoneal drainage.

TYPE OF STUDY

Prognosis study.

LEVEL OF EVIDENCE

Level II.

Development of an improved murine model of necrotizing enterocolitis shows the importance of neutrophils in NEC pathogenesis

Various research models to induce necrotizing enterocolitis (NEC) in animals exist, yet significant differences in NEC severity between murine animal models and human patients persist. One possible explanation for the difference in severity may be the variance in neutrophil concentration among newborn humans (50-70%) in comparison to neonatal mice (10-25%). However, neutrophil activity has yet to be evaluated in NEC pathogenesis. Thus, the aim of the study was to evaluate the effects of altered neutrophil concentrations in neonatal mice while simultaneously undergoing a NEC induction. A total of 44 neonatal mice were included in this study and 40 were subjected to an established NEC induction paradigm and 4 were assigned a sham group. Of the 40 mice, 30 received granulocyte-colony stimulating factor (G-CSF) on a daily basis, while 10 were used as controls (receiving inactivated G-CSF). Mice undergoing G-CSF treatment were further divided into two subgroups: (1) wildtype and (2) ELANE-knockout (KO). ELANE - KO mice are incapable of producing neutrophil elastase (NE) and were used to evaluate the role of neutrophils in NEC. For each of the groups, the following metrics were evaluated: survival, NEC severity, tissue damage, neutrophil count and activation, and NETs formation. An improved murine model of NEC was developed using (1) Lipopolysaccharides and Neocate gavage feeding, (2) hypoxia, and (3) G-CSF administration. The results suggest that the addition of G-CSF resulted in significantly elevated NEC manifestation rates with consequent tissue damage and intestinal inflammation, without affecting overall mortality. Animals without functioning NE (ELANE-KO) appeared to have been protected from NEC development. This study supports the importance of neutrophils in NEC pathogenesis. The optimized NEC induction paradigm, using G-CSF administration, resulted in elevated neutrophil counts, resembling those of neonatal humans. Elevation of neutrophil levels significantly improved NEC disease manifestation by modeling human physiology more accurately than current NEC models. Thus, in the future, murine NEC experiments should include the elevation of neutrophil levels to improve the transition of research findings from mice to humans.

Contemporary Outcomes for Infants with Necrotizing Enterocolitis-A Systematic Review

OBJECTIVE

To develop an accurate understanding of outcomes for necrotizing enterocolitis (NEC) to inform parental counseling, clinical care, and research agendas.

STUDY DESIGN

A systematic review of recent (January 2010-January 2018) large cohort studies reporting outcomes of infants who developed NEC. Only studies reporting national, regional, or multicenter outcomes of NEC in high income countries were included. Outcomes assessed were mortality, neurodevelopmental outcome, and intestinal failure. Meta-analyses were used to generate summary statistics for these outcomes.

RESULTS

Of 1375 abstracts, 38 articles were included. Overall mortality was 23.5% in all neonates with confirmed NEC (Bell stage 2a+) (95% CI 18.5%-28.8%), 34.5% (30.1%-39.2%) for neonates that underwent surgery for NEC, 40.5% (37.2%-43.8%) for extremely low birthweight infants (<1000 g), and 50.9% (38.1%-63.5%) for extremely low birthweight infants with surgical NEC. Studies examining causes of neonatal mortality showed NEC is responsible for around 1 in 10 of all neonatal deaths. Neurodevelopmental disability was reported in 4 studies at between 24.8% and 61.1% (1209 total NEC cases). Three studies reported intestinal failure with an incidence of 15.2%-35.0% (n = 1370). The main limitation of this review is the lack of an agreed definition for diagnosing NEC and the differences in the way that outcomes are reported.

CONCLUSIONS

Mortality following NEC remains high. These contemporary data inform clinical care and justify ongoing research efforts. All infants with NEC should have long-term neurodevelopmental assessment. Data on the long-term risk of intestinal failure are limited.

TRIAL REGISTRATION

CRD42018094791.

Jungen sterben häufiger an nekrotisierender Enterokolitis

Hintergrund

In den letzten Jahren verringerte sich die frühgeburtliche Morbidität und Mortalität über Ländergrenzen hinweg deutlich. Allen Untersuchungen gemeinsam ist aber eine höhere Betroffenheit und Sterblichkeit von Jungen gegenüber Mädchen, insbesondere bei der nekrotisierenden Enterokolitis.

Fragestellung

Besteht in Deutschland auf Basis der amtlichen Krankenhausstatistik eine höhere Inzidenz oder Sterblichkeit von Jungen an nekrotisierender Enterokolitis?

Material und Methoden

Die Autoren werteten die Diagnosedaten der amtlichen Krankenhausstatistik für die Jahre 2000–2017 für die Hauptdiagnose P77 – nekrotisierende Enterokolitis –, getrennt nach Geschlechtern und Überleben, aus. Der Zusammenhang zwischen Geschlecht und Versterben resp. Erkrankungshäufigkeit wurde mittels einseitigem χ2-Test auf ein höheres Risiko für Jungen untersucht.

Ergebnisse

Zwischen 2000 und 2017 hatten 3119 Frühgeborene die Hauptdiagnose nekrotisierende Enterokolitis, davon 1769 Jungen (0,27 ‰ der männlichen Lebendgeburten) und 1350 Mädchen (0,22 ‰ der weiblichen Lebendgeburten). Jungen haben ein höheres Risiko, an nekrotisierender Enterokolitis zu erkranken (relatives Risiko 1,24, 95 %-Konfidenzintervall: 1,17–∞, p < 0,001) und zu versterben (relatives Risiko 1,25, 95 %-Konfidenzintervall: 1,02–∞, p = 0,036).

Diskussion

Jungen erkranken und sterben häufiger an nekrotisierender Enterokolitis als Mädchen. Allerdings erfasst die amtliche Statistik nicht die leichteren Fälle einer nekrotisierenden Enterokolitis, da nur die Hauptdiagnose erfasst wird. Überdies ermöglicht die amtliche Statistik keine Adjustierung für verzerrende Faktoren. Die sekundäre Datennutzung der Qualitätssicherungsdaten der Neonatalerhebung könnte eine detailliertere Untersuchung dieser Fragestellung ermöglichen.

Necrotizing Enterocolitis and Associated Mortality in Neonates With Congenital Heart Disease: A Multi-Institutional Study

OBJECTIVE

There are scarce data about the prevalence and mortality of necrotizing enterocolitis in neonates with congenital heart disease. The purpose of this study is to provide a multi-institutional description and comparison of the overall prevalence and mortality of necrotizing enterocolitis in neonates with congenital heart disease.

DESIGN

Retrospective multi-institutional study.

SETTING

The Pediatric Health Information System database.

PATIENTS

Neonates with congenital heart disease between 2004 and 2014.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary study measure is the prevalence of necrotizing enterocolitis. Secondary measures include in-hospital mortality, hospital charges, ICU length of stay, hospital length of stay, and 30-day readmission. The prevalence of necrotizing enterocolitis was 3.7% (1,448/38,770) and varied significantly among different congenital heart disease diagnoses. The lowest prevalence of necrotizing enterocolitis was in transposition of the great arteries (n = 104, 2.1%). Compared with transposition of the great arteries, necrotizing enterocolitis occurred more frequently in neonates with hypoplastic left heart syndrome (odds ratio, 2.7; 95% CI, 2.1-3.3), truncus arteriosus (odds ratio, 2.6; 95% CI, 1.9-3.5), common ventricle (odds ratio, 2.1; 95% CI, 1.5-2.8), and aortic arch obstruction (odds ratio, 1.4; 95% CI, 1.1-1.7). Prematurity is a significant risk factor for necrotizing enterocolitis and for mortality in neonates with necrotizing enterocolitis, conferring varying risk by cardiac diagnosis. Unadjusted mortality associated with necrotizing enterocolitis was 24.4% (vs 11.8% in neonates without necrotizing enterocolitis; p < 0.001), and necrotizing enterocolitis increased the adjusted mortality in neonates with transposition of the great arteries (odds ratio, 2.5; 95% CI, 1.5-4.4), aortic arch obstruction (odds ratio, 1.8; 95% CI, 1.3-2.6), and tetralogy of Fallot (odds ratio, 1.6; 95% CI, 1.1-2.4). Necrotizing enterocolitis was associated with increased hospital charges (p < 0.0001), ICU length of stay (p = 0.001), and length of stay (p = 0.001).

CONCLUSIONS

The prevalence of necrotizing enterocolitis among neonates with congenital heart disease is 3.7% and is associated with increased in-hospital mortality, length of stay, and hospital charges. The prevalence and associated mortality of necrotizing enterocolitis in congenital heart disease vary among different heart defects.

Incidence, Treatment, and Outcome Trends of Necrotizing Enterocolitis in Preterm Infants: A Multicenter Cohort Study

Background: Data regarding the incidence and mortality of necrotizing enterocolitis trends are scarce in the literature. Recently, some preventive strategies have been confirmed (probiotics) or increased (breastfeeding rate). This study aims to describe the trends of necrotizing enterocolitis incidence, treatment, and mortality over the last decade in Spain. Methods: Multicenter cohort study with data from the Spanish Neonatal Network-SEN1500 database. The study period comprised from January 2005 to December 2017. Preterm infants <32 weeks of gestational age at birth without major congenital malformations were included for analysis. The main study outcomes were necrotizing enterocolitis incidence, co-morbidity (bronchopulmonary dysplasia, late-onset sepsis, cystic periventricular leukomalacia, retinopathy of prematurity, acute kidney injury), mortality, and surgical/non-surgical treatment. Results: Among the 25,821 included infants, NEC incidence was 8.8% during the whole study period and remained stable when comparing 4-year subperiods. However, more cases were surgically treated (from 48.8% in 2005-2008 to 70.2% in 2015-2017, p < 0.001). Mortality improved from 36.7% in the 2005-2008 to 26.6% in 2015-2017 (p < 0.001). Breastfeeding rates improved over the studied years (24.3% to 40.5%, p < 0.001), while gestational age remained invariable (28.5 weeks, p = 0.20). Prophylactic probiotics were implemented during the study period in some units, reaching 18.6% of the patients in 2015-2017. Conclusions: The incidence of necrotizing enterocolitis remained stable despite the improvement regarding protective factors frequency. Surgical treatment became more frequent over the study period, whereas mortality decreased.

Preventive strategies and factors associated with surgically treated necrotising enterocolitis in extremely preterm infants: an international unit survey linked with retrospective cohort data analysis

OBJECTIVES

To compare necrotising enterocolitis (NEC) prevention practices and NEC associated factors between units from eight countries of the International Network for Evaluation of Outcomes of Neonates, and to assess their association with surgical NEC rates.

DESIGN

Prospective unit-level survey combined with retrospective cohort study.

SETTING

Neonatal intensive care units in Australia/New Zealand, Canada, Finland, Israel, Spain, Sweden, Switzerland and Tuscany (Italy).

PATIENTS

Extremely preterm infants born between 24⁰ to 28⁶ weeks' gestation, with birth weights<1500 g, and admitted between 2014-2015.

EXPOSURES

NEC prevention practices (probiotics, feeding, donor milk) using responses of an on-line pre-piloted questionnaire containing 10 questions and factors associated with NEC in literature (antenatal steroids, c-section, indomethacin treated patent ductus arteriosus and sepsis) using cohort data.

OUTCOME MEASURES

Surgical NEC rates and death following NEC using cohort data.

RESULTS

The survey response rate was 91% (153 units). Both probiotic provision and donor milk availability varied between 0%-100% among networks whereas feeding initiation and advancement rates were similar in most networks. The 9792 infants included in the cohort study to link survey results and cohort outcomes, revealed similar baseline characteristics but considerable differences in factors associated with NEC between networks. 397 (4.1%) neonates underwent NEC surgery, ranging from 2.4%-8.4% between networks. Standardised ratios for surgical NEC were lower for Australia/New Zealand, higher for Spain, and comparable for the remaining six networks.

CONCLUSIONS

The variation in implementation of NEC prevention practices and in factors associated with NEC in literature could not be associated with the variation in surgical NEC incidence. This corroborates the current lack of consensus surrounding the use of preventive strategies for NEC and emphasises the need for research.

Incidence and risk of necrotizing enterocolitis in Denmark from 1994-2014

Introduction. We suspected that the incidence of NEC in Denmark had increased during the last 20 years but hypothesized that this could be explained by the increased neonatal survival. Methods. We conducted a retrospective, observational cohort study of all registered liveborn infants in Denmark in the period from January 1, 1994 to December 31, 2014. Data were obtained from the Medical Birth Registry, National Patient Register, and Cause of Death register in Denmark. The primary outcome was the registration of NEC (ICD-10: DP77.9) during a hospital admission within 6 months after birth. The statistical analysis used ‘death before NEC’ as a competing risk. Results. The cohort consisted of 1,351,675 infants, of which 8,059 died. There was a strongly significant decreasing risk of death over the period for the all infants (p<0.0001 in all gestational age groups). In total, 994 infants were diagnosed with NEC which lead to an incidence of 7.4 per 10,000 live-born infants. During the observation period, the incidence increased from 6.3 to 7.9 per 10,000 births (p = 0.006). When accounting for ‘death before NEC’ as a competing risk, the increase could be explained by the increased neonatal survival. There was, however, a GA-group/epoch interaction (p = 0.008) in the cause-specific hazard ratios with a trend towards an increasing risk of NEC in the most preterm infants and a decreasing risk of NEC in the term infants. Conclusion. While the overall incidence of NEC increased over the study period, the overall risk of NEC did not increase when considering the increased survival. Nevertheless, there seemed to be an increased risk of NEC in the most premature infants which was masked by a decreased risk in the term infants. This study suggests that research to prevent NEC in the most preterm infants is more important now than ever.

Practice variations and rates of late onset sepsis and necrotizing enterocolitis in very preterm born infants, a review

The burden of late onset sepsis (LOS) and necrotizing enterocolitis (NEC) remains high for newborns in low- and high-income countries. Very preterm born infants born below 32 weeks gestation are at highest risk because their immune system is not yet adapted to ex-utero life, providing intensive care frequently compromises their skin or mucosa and they require a long duration of hospital stay. An epidemiological overview is difficult to provide because there is no mutually accepted definition available for either LOS or NEC. LOS incidence proportions are generally reported based on identified blood culture pathogens. However, discordance in minimum day of onset and whether coagulase negative staphylococci or fungi should be included into the reported proportions lead to variation in reported incidences. Complicating the comparison are the absence of biomarkers, ancillary lab tests or prediction models with sufficiently high positive and/or negative predictive values. The only high negative predictive values result from negative blood culture results with negative lab results allowing to discontinue antibiotic treatment. Similar difficulties exist in reporting and diagnosing NEC. Although most publications base their proportions on a modified version of Bell's stage 2 or 3, comparisons are made difficult by the multifactorial nature of the disease reflecting several pathways to intestinal necrosis, the absence of a reliable biomarker and the unclear differentiation from spontaneous intestinal perforations. Comparable reports in very low birthweight infants range between 5% and 30% for LOS and 1.6% to 7.1% for NEC. Evidence based guidelines to support treatment are missing. Treatment for LOS remains largely empirical and focused mainly on antibiotics. In the absence of a clear diagnosis, even unspecific early warning signals need to be met with antibiotic treatment. Cessation after negative blood culture is difficult unless the child was asymptomatic from the beginning. As a result, antibiotics are the most commonly prescribed medications, but unnecessary exposure may result in increased risk for mortality, NEC, further infections and childhood obesity or asthma. Finding ways to limit antibiotic use are thus important and have shown a large potential for improvement of care and limitation of cost. Over recent decades, none of the attempts to establish novel therapies have succeeded. LOS and NEC proportions remained mostly stable. During the past 10 years however, publications emerged reporting a reduction, sometimes by almost 50%. Most concern units participating in a surveillance system using quality improvement strategies to prevent LOS or NEC (e.g., hand hygiene, evidence based "bundles", feeding onset, providing own mother's milk). We conclude that these approaches display a potential for wider spread reduction of LOS and NEC and for a subsequently more successful development of novel therapies as these often address the same pathways as the prevention strategies.

Increased risk of rickets but not fractures during childhood and adolescence following necrotizing enterocolitis among children born preterm in Sweden

BACKGROUND

The aim was to clarify whether children born preterm with a history of necrotizing enterocolitis (NEC) had an increased risk of rickets, fractures, and/or vitamin D deficiency during childhood and adolescence compared to controls without NEC, matched for gestational age.

METHODS

All infants born in Sweden between 1987 and 2009 with a gestational age <32 + 0 weeks and a diagnosis of NEC were identified. Totally, 465 children with a history of NEC and 2127 controls were included. International Classification of Diseases codes for all categories of fractures, rickets, vitamin D deficiency, and malnutrition were analyzed.

RESULTS

In total, 94 of the 465 children with NEC died within 28 days. Of the 2127 controls, 288 died within 28 days. Among the remaining 371 NEC cases, 39 fracture occasions were identified. The 1839 controls had 204 fracture occasions. There was no significant difference in fractures. Rickets was diagnosed in 11 (3%) of the children with a history of NEC compared to 21 (1%) of the controls (odds ratio 2.65, 95% CI 1.26-5.53, p = 0.007).

CONCLUSIONS

This study showed an increased risk of rickets but not fractures during childhood and adolescence in children born preterm and with a history of NEC, compared to matched controls.

Validation of the diagnosis of necrotising enterocolitis in a Swedish population-based observational study

Aim

The definition of necrotising enterocolitis (NEC) is based on clinical and radiological signs that can be difficult to interpret. The aim of the present study was to validate the incidence of NEC in the Extremely Preterm Infants in Sweden Study (EXPRESS)

Methods

The EXPRESS study consisted of all 707 infants born before 27 + 0 gestational weeks during the years 2004–2007 in Sweden. Of these infants, 38 were recorded as having NEC of Bell stage II or higher. Hospital records were obtained for these infants. Furthermore, to identify missed cases, all infants with a sudden reduction of enteral nutrition, in the EXPRESS study were identified (n = 71). Hospital records for these infants were obtained. Thus, 108 hospital records were obtained and scored independently by two neonatologists for NEC.

Results

Of 38 NEC cases in the EXPRESS study, 26 were classified as NEC after validation. Four cases not recorded in the EXPRESS study were found. The incidence of NEC decreased from 6.3% to 4.3%.

Conclusion

Validation of the incidence of NEC revealed over‐ and underestimation of NEC in the EXPRESS study despite carefully collected data. Similar problems may occur in other national data sets or quality registers.

Clostridia and necrotizing enterocolitis in preterm neonates

Necrotizing enterocolitis (NEC) is the most severe life threatening gastrointestinal disease among preterm neonates. NEC continues to account for substantial morbidity and mortality in neonatal intensive care units worldwide. Although its pathogenesis remains incompletely elucidated, NEC is recognized as a multifactorial disease involving intestinal unbalanced inflammatory response, feeding strategies, and bacterial colonization. Epidemiological studies, clinical signs, and animal models support the participation of anaerobic bacteria, particularly clostridia species, in NEC development. Colonization by clostridia seems particularly deleterious. The present review is the opportunity to propose an update on the role of clostridia and NEC.

Arguments against routine administration of probiotics for NEC prevention

PURPOSE OF REVIEW

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality among premature neonates. Although randomized trials have shown that probiotics may be efficacious in the prevention of NEC, their use has not been universally adopted in the neonatal intensive care unit (NICU). Caveats regarding routine probiotic supplementation for the prevention of NEC are summarized in this review.

RECENT FINDINGS

Accumulating evidence indicates that prophylactic probiotic supplementation in preterm infants can reduce the incidence of NEC. However, substantial knowledge gaps, regulatory issues, and implementation challenges should be addressed before probiotics are introduced as standard of care for all preterm neonates. Limitations of published trial data have made it challenging to define regimens that optimize efficacy and safety in specific patient subgroups. Moreover, the current probiotic market lacks rigorous regulatory oversight, which could raise concerns about the quality and safety of probiotic products. Finally, implementation pitfalls include risks of cross-colonization and resource requirements to monitor and mitigate potential adverse events.

SUMMARY

Probiotics have shown promise in the prevention of NEC. However, there is insufficient evidence to guide the selection of optimal regimens. Furthermore, issues related to regulatory and institutional oversight should be addressed before supplementation is routinely implemented in NICUs.

Challenges in Advancing Necrotizing Enterocolitis Research

Progressing necrotizing enterocolitis research is difficult because the disease is variable in presentation, there are difficulties in making a precise diagnosis, a reliable agreed case-definition is currently lacking, and there is a paucity of preclinical research to identify etiologic targets. The major challenges of the cost of clinical trials and need for long-term outcome ascertainment could be eased through incorporation of novel randomization approaches and data collection into routine care, and collaboration between public-sector and industry funders.

Colostrum immunoglobulins and oxidative capacity may be affected by infant sex and maternal age and parity

Background/aim

The aims of this study were to determine the levels of the total antioxidant status (TAS), the total oxidant status (TOS), the oxidative stress index (OSI), and the concentration of immunoglobulin A (IgA) and M (IgM) in colostrum, and evaluate relationships between these parameters and maternal age, maternal parity, and infant sex.

Materials and methods

The analysis was performed in serum samples of colostrum which were collected from 90 mothers on the first day of lactation between 10:00 and 12:00 AM.

Results

The measurements established that no significant association existed between the TAS level of colostrum and parity, maternal age, or infant sex. However, mothers 18 to 30 years of age had significantly lower colostrum TOS and OSI levels compared with mothers older than 30 years of age. IgA and IgM values of the colostrum of primiparous mothers were significantly higher than those of multiparous mothers, whereas no correlations existed with the age of the mother. Additionally, significantly higher colostrum IgA and IgM values were observed in female infants fed colostrum compared with male infants.

Conclusion

In conclusion, sex-based hormonal changes in mothers during pregnancy may be associated with the different colostral immunoglobulin levels for male and female infants.

A critical analysis of risk factors for necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common serious gastrointestinal morbidity in preterm infants. A number of risk factors for NEC have been reported in the literature. With the exception of decreasing gestational age, decreasing birth weight and formula feeding, there is disagreement on the importance of reported risk factors with uncertain causality. Causal risk factors may be observed at any time before the onset of NEC, including prior to an infant's birth. The purpose of this review is to examine the existing literature and summarize risk factors for NEC. This review may be helpful in understanding the epidemiology of NEC and inform the measurement and assessment of risks factors for NEC in research studies and quality improvement projects.

Probiotic Lactococcus lactis decreases incidence and severity of necrotizing enterocolitis in a preterm animal model

BACKGROUND

Necrotizing enterocolitis (NEC) persists as the most common and serious gastrointestinal disorder among premature infants. Lactococcus lactis (LL), a lactic acid producing bacteria commonly found in buttermilk and cheese products, has several unique properties making it an ideal probiotic for neonates. We evaluated if the probiotic LL prevents development of NEC in a preterm rabbit model with Cronobacter sakazakii (CS).

METHODS

Two-day preterm New Zealand white rabbit pups were randomly assigned to three diets: control (no additives), CS, and CS+LL. Pups were gavage fed and given daily oral ranitidine and indomethacin. Anal blockage was performed using tissue adhesive. Subjects were sacrificed on day four, with tissue from distal ileum and proximal colon graded for NEC by a pediatric pathologist blinded to group assignments. Outcomes were compared using Fisher's exact test.

RESULTS

All pups in the control group survived to sacrifice and none developed NEC. Survival was 26% higher (p = 0.03) and incidence of NEC 51% less (P < 0.001) in CS+LL group compared to CS group. Of the pups that developed NEC, all pups in the CS+LL group had Grade 1 NEC, while one-third of pups in the CS group developed Grades 2-4 NEC.

CONCLUSIONS

In the presence of CS, LL is protective against development of NEC in a preterm rabbit model. Future studies are needed that evaluate utilization of prophylactic probiotics in the neonatal intensive care unit to determine if this intervention can successfully decrease rates of NEC in preterm infants.

Maternal pregnancy-induced hypertension increases subsequent neonatal necrotizing enterocolitis risk: A nationwide population-based retrospective cohort study in Taiwan

The utero-placental ischemia induced by pregnancy-induced hypertension (PIH) could lead to fetal hypoxia and proinflammatory cytokine release, which are associated with the development of neonatal necrotizing enterocolitis (NEC). However, a few studies have investigated the relationship between PIH and neonatal NEC and have produced controversial results. Therefore, we attempted to assess the relationship between PIH and the subsequent neonatal NEC risk and identify predictive risk factors.Patients with newly diagnosed PIH were recruited from the Taiwan National Health Insurance Research Database (NHIRD). For each participant, 4 age- and delivery-year-matched participants without PIH were randomly selected. A multivariable logistic regression was performed for the identification of the predictive risk factors for neonatal NEC.Among the 23.3 million individuals registered in the NHIRD, 29,013 patients with PIH and 116,052 matched controls were identified. For the multivariable analysis, maternal PIH was associated with an increased risk of subsequent neonatal NEC development (odds ratio [OR] 1.86, 95% confidence interval [CI] 1.08-3.21, P = .026). Furthermore, single parity (OR 2.06, 95% CI 1.12-3.77, P = .019), preterm birth (OR 5.97, 95% CI 3.49-10.20, P < .001), multiple gestations (OR 2.25, 95% CI 1.22-4.14, P = .010), and intrauterine growth restriction (IUGR) (OR 3.59, 95% CI 2.06-6.24, P < .001) were independent risk factors for the development of subsequent neonatal NEC.Maternal PIH increases the risk for developing neonatal NEC. Furthermore, primiparity, preterm birth, multiple gestations, and IUGR were independent risk factors for neonatal NEC.

Growth morbidity in extremely low birth weight survivors of necrotizing enterocolitis at discharge and two-year follow-up

PURPOSE

The purpose of this study was to examine postnatal growth outcomes and predictors of growth failure at 18-24months corrected age among extremely low birth weight (ELBW) survivors of necrotizing enterocolitis (NEC) compared to survivors without NEC.

METHODS

Data were collected prospectively on ELBW (22-27weeks gestation or 401-1000g birth weight) infants born 2000-2013 at 46 centers participating in the Vermont Oxford Network follow-up project. Severe growth failure was defined as <3rd percentile weight-for-age.

RESULTS

There were 9171 evaluated infants without NEC, 416 with medical NEC, and 462 with surgical NEC. Rates of severe growth failure at discharge were higher among infants with medical NEC (56%) and surgical NEC (61%), compared to those without NEC (36%). At 18-24months follow-up, rates of severe growth failure decreased and were similar between without NEC (24%), medical NEC (24%), and surgical NEC (28%). On multivariable analysis, small for gestational age, chronic lung disease, severe intraventricular hemorrhage or cystic periventricular leukomalacia, severe growth failure at discharge, and postdischarge tube feeding predicted <3rd percentile weight-for-age at follow-up.

CONCLUSIONS

ELBW survivors of NEC have higher rates of severe growth failure at discharge. While NEC is not associated with severe growth failure at follow-up, one quarter of ELBW infants have severe growth failure at 18-24months.

TYPE OF STUDY

Prognosis study.

LEVEL OF EVIDENCE

II.

There is an association between disease location and gestational age at birth in newborns submitted to surgery due to necrotizing enterocolitis

OBJECTIVES

To evaluate if there are differences regarding disease location and mortality of necrotizing enterocolitis, according to the gestational age at birth, in newborns submitted to surgery due to enterocolite.

METHODS

A historical cohort study of 198 newborns submitted to surgery due to necrotizing enterecolitis in a tertiary hospital, from November 1991 to December 2012. The newborns were divided into different categories according to gestational age (<30 weeks, 30-33 weeks and 6 days, 34-36 weeks and 6 days, and ≥37 weeks), and were followed for 60 days after surgery. The inclusion criterion was the presence of histological findings of necrotizing enterocolitis in the pathology. Patients with single intestinal perforation were excluded.

RESULTS

The jejunum was the most commonly affected site in extremely premature infants (p=0.01), whereas the ileum was the most commonly affected site in premature infants (p=0.002), and the colon in infants born at term (p<0.001). With the increasing gestational age, it was observed that intestinal involvement decreased for the ileum and the jejunum (decreasing from 45% to 0% and from 5% to 0%, respectively), with a progressive increase in colon involvement (0% to 84%). Total mortality rate was 45.5%, and no statistical difference was observed in the mortality at different gestational ages (p=0.287).

CONCLUSIONS

In newborns submitted to surgery due to necrotizing enterocolitis, the disease in extremely preterm infants was more common in the jejunum, whereas in preterm infants, the most affected site was the ileum, and in newborns born close to term, it was the colon. No difference in mortality was observed according to the gestational age at birth.

Routine Supplementation of Lactobacillus rhamnosus GG and Risk of Necrotizing Enterocolitis in Very Low Birth Weight Infants

OBJECTIVE

To evaluate if routine supplementation of Lactobacillus rhamnosus GG ATCC 53103 (LGG) is associated with a decreased risk of necrotizing enterocolitis in very low birth weight (VLBW) infants.

STUDY DESIGN

Retrospective observational cohort study of VLBW (<1500 g) infants at a single center from 2008 to 2016. LGG supplementation with Culturelle at a dose of 2.5 to 5 × 10⁹ CFU/day began in 2014. We used multivariable logistic regression to evaluate the association between LGG supplementation and necrotizing enterocolitis (modified Bell stage IIA or greater), after adjusting for potential confounders. We also compared changes in necrotizing enterocolitis incidence before and after implementation of LGG using a statistical process control chart.

RESULTS

We evaluated 640 VLBW infants with a median gestational age of 28.7 weeks (IQR 26.3-30.6); 78 (12%) developed necrotizing enterocolitis. The median age at first dose of LGG was 6 days (IQR 3-10), and duration of supplementation was 32 days (IQR 18-45). The incidence of necrotizing enterocolitis in the epoch before LGG implementation was 10.2% compared with 16.8% after implementation. In multivariable analysis, LGG supplementation was associated with a higher risk of necrotizing enterocolitis (aOR 2.10, 95 % CI 1.25-3.54, P = .005). We found no special cause variation in necrotizing enterocolitis after implementation of LGG supplementation. There were no episodes of Lactobacillus sepsis during 5558 infant days of LGG supplementation.

CONCLUSIONS

In this study, routine LGG supplementation was not associated with a decreased risk of necrotizing enterocolitis. Our findings do not support the use of the most common probiotic preparation currently supplemented to VLBW infants in the US.

The role of imaging in the management of necrotising enterocolitis: a multispecialist survey and a review of the literature

Objectives

To investigate current practices and perceptions of imaging in necrotising enterocolitis (NEC) according to involved specialists, put them in the context of current literature, and identify needs for further investigation.

Methods

Two hundred two neonatologists, paediatric surgeons, and radiologists answered a web-based questionnaire about imaging in NEC at their hospitals. The results were descriptively analysed, using proportion estimates with 95% confidence intervals.

Results

There was over 90% agreement on the value of imaging for confirmation of the diagnosis, surveillance, and guidance in decisions on surgery as well as on abdominal radiography as the first-choice modality and the most important radiographic signs. More variation was observed regarding some indications for surgery and the use of some ultrasonographic signs. Fifty-eight per cent stated that ultrasound was used for NEC at their hospital. Examination frequency, often once daily or more but with considerable variations, and projections used in AR were usually decided individually rather than according to fixed schedules. Predicting the need of surgery was regarded more important than formal staging.

Conclusion

Despite great agreement on the purposes of imaging in NEC and the most important radiographic signs of the disease, there was considerable diversity in routines, especially regarding examination frequency and the use of ultrasound. Apart from continuing validation of ultrasound, important objectives for future studies include definition of the supplementary roles of both imaging modalities in relation to other diagnostic parameters and evaluation of various imaging routines in relation to timing of surgery, complications, and mortality rate.

Key Points

• Imaging is an indispensable tool in the management of necrotising enterocolitis

• Predicting the need of surgery is regarded more important than formal staging

• There is great consensus on important signs of NEC on abdominal radiography

• There is more uncertainty regarding the role of ultrasound

• Individualised management is preferred over standardised diagnostic algorithms

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5362-x) contains supplementary material, which is available to authorized users.

Maternal, fetal and perinatal factors associated with necrotizing enterocolitis in Sweden. A national case-control study

OBJECTIVE

To analyze associations of maternal, fetal, gestational, and perinatal factors with necrotizing enterocolitis in a matched case-control study based on routinely collected, nationwide register data.

STUDY DESIGN

All infants born in 1987 through 2009 with a diagnosis of necrotizing enterocolitis in any of the Swedish national health care registers were identified. For each case up to 6 controls, matched for birth year and gestational age, were selected. The resulting study population consisted of 720 cases and 3,567 controls. Information on socioeconomic data about the mother, maternal morbidity, pregnancy related diagnoses, perinatal diagnoses of the infant, and procedures in the perinatal period, was obtained for all cases and controls and analyzed with univariable and multivariable logistic regressions for the whole study population as well as for subgroups according to gestational age.

RESULTS

In the study population as a whole, we found independent positive associations with necrotizing enterocolitis for isoimmunization, fetal distress, cesarean section, neonatal bacterial infection including sepsis, erythrocyte transfusion, persistent ductus arteriosus, cardiac malformation, gastrointestinal malformation, and chromosomal abnormality. Negative associations were found for maternal weight, preeclampsia, maternal urinary infection, premature rupture of the membranes, and birthweight. Different patterns of associations were seen in the subgroups of different gestational age.

CONCLUSION

With some interesting exceptions, especially in negative associations, the results of this large, population based study, are in keeping with earlier studies. Although restrained by the limitations of register data, the findings mirror conceivable pathophysiological processes and underline that NEC is a multifactorial disease.

Incidence of neonatal necrotising enterocolitis in high-income countries: a systematic review

OBJECTIVE

To conduct a systematic review of neonatal necrotising enterocolitis (NEC) rates in high-income countries published in peer-reviewed journals.

METHODS

We searched MEDLINE, Embase and PubMed databases for observational studies published in peer-reviewed journals. We selected studies reporting national, regional or multicentre rates of NEC in 34 Organisation for Economic Co-operation and Development countries. Two investigators independently screened studies against predetermined criteria. For included studies, we extracted country, year of publication in peer-reviewed journal, study time period, study population inclusion and exclusion criteria, case definition, gestation or birth weight-specific NEC and mortality rates.

RESULTS

Of the 1888 references identified, 120 full manuscripts were reviewed, 33 studies met inclusion criteria, 14 studies with the most recent data from 12 countries were included in the final analysis. We identified an almost fourfold difference, from 2% to 7%, in the rate of NEC among babies born <32 weeks' gestation and an almost fivefold difference, from 5% to 22%, among those with a birth weight <1000 g but few studies covered the entire at-risk population. The most commonly applied definition was Bell's stage ≥2, which was used in seven studies. Other definitions included Bell's stage 1-3, definitions from the Centers for Disease Control and Prevention, International Classification for Diseases and combinations of clinical and radiological signs as specified by study authors.

CONCLUSION

The reasons for international variation in NEC incidence are an important area for future research. Reliable inferences require clarity in defining population coverage and consistency in the case definition applied. PROSPERO INTERNATIONAL PROSPECTIVE REGISTER OF SYSTEMATIC REVIEWS REGISTRATION NUMBER: CRD42015030046.

Intestinal failure after necrotising enterocolitis: incidence and risk factors in a Swedish population-based longitudinal study

BACKGROUND AND OBJECTIVE

Paediatric intestinal failure (IF) is a disease entity characterised by gut insufficiency often related to short bowel syndrome. It is commonly caused by surgical removal of a large section of the small intestine in association with necrotising enterocolitis (NEC), which usually affects premature infants. This study investigated the incidence and risk of IF in preterm infants with or without NEC.

DESIGN

A matched cohort study to investigate the incidence and risk factors for IF in a population-based setting in Sweden from 1987 to 2009 using the Swedish Patient Register.

PARTICIPANTS

Infants with a diagnosis of NEC (n=720) were matched for gestational age and year of birth with reference individuals without NEC (n=3656). The study cohort was censored at death, IF or at end of follow-up (2 years of age). We calculated HRs with 95%CIs for IF using Cox regression, adjusting for pertinent perinatal factors.

RESULTS

IF was 15 times more common in the infants with NEC compared with the reference infants (HR=7.2, with 95% CI 3.7 to 14.0). Other risk factors for IF were small for gestational age, extreme preterm birth and abdominal surgery. Neonatal mortality in infants with NEC decreased from 20.6% in 1987-1993 to 10.4% in 2007-2009.

CONCLUSION

IF was more common in the infants with NEC but was also linked to extreme preterm birth, a history of abdominal surgery and small for gestational age. IF was more common at the end of the study period, indicating that it increases when more preterm infants with NEC survive the neonatal period.

Single-Immunoglobulin Interleukin-1-Related Receptor regulates vulnerability to TLR4-mediated necrotizing enterocolitis in a mouse model

BackgroundThe mechanisms underlying aberrant activation of intestinal Toll-like receptor 4 (TLR4) signaling in necrotizing enterocolitis (NEC) remain unclear. In this study, we examined the role of single-immunoglobulin interleukin-1 receptor-related molecule (SIGIRR), an inhibitor of TLR signaling, in modulating experimental NEC vulnerability in mice.MethodsExperimental NEC was induced in neonatal wild-type and SIGIRR-/- mice using hypoxia, formula-feeding, and lipopolysaccharide administration. Intestinal TLR canonical signaling, inflammation, apoptosis, and severity of experimental NEC were examined at baseline and after NEC induction in mice.ResultsSIGIRR is developmentally regulated in the neonatal intestine with a restricted expression after birth and a gradual increase by day 8. At baseline, breast-fed SIGIRR-/- mouse pups exhibited low-grade inflammation and TLR pathway activation compared with SIGIRR+/+ pups. With experimental NEC, SIGIRR-/- mice had significantly more intestinal interleukin (IL)-1β, KC (mouse homolog to IL-8), intercellular adhesion molecule-1 (ICAM-1), and interferon-beta (IFN-β) expression in association with the amplified TLR pathway activation. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining, cleaved caspase 3, and severity of intestinal injury with NEC were worse in SIGIRR-/- mice in comparison with SIGIRR+/+ mice.ConclusionSIGIRR is a negative regulator of TLR4 signaling in the developing intestine, and its insufficiency results in native intestinal TLR hyper-responsiveness conducive to the development of severe experimental NEC in mice.