Center Differences in NEC within One Health-Care System May Depend on Feeding Protocol

ABSTRACT

We tabulated the incidence of necrotizing enterocolitis (NEC) during a recent 4-year period among three neonatal intensive care units (NICUs) within a single health-care system. We then sought associations to explain differences in NEC incidence between the centers. Between January 1, 2002, and December 31, 2005, 6787 neonates were admitted to the three NICUs. The incidence of NEC (Bell's stage II or higher) among these patients was correlated with birthweight, gestational age, maternal and neonatal demographics, and various events and practices. These events and practices included feeding practices, the management of patent ductus arteriosus, rates of systemic bacterial and fungal infection, transfers to the regional children's hospital for surgical treatment, and mortality rate. Bell's stage II or higher NEC was documented in 131 of 6787 NICU patients. The incidence was 7.4% among those with birthweights < 750 g (16 of 217), 6.9% among those of birthweights 750 to 1250 g (36 of 519), and 1.3% (79 of 6051) among those with birthweights > 1250 g. Center A had an incidence of NEC significantly higher than the other two, accounting for 72% of the total cases (94 of 131). Among patients < 1250 g, Center A had a rate of NEC of 14.5%; Centers B (2.3%) and C (2.3%) had lower rates (p < 0.0001). After controlling for gestational age, birthweight, small for gestational age status, and Apgar scores, the overall odds ratio of developing NEC in Center A, compared with the other two, was 21.6 (95% confidence interval, 14.7 to 31.6). This difference could not be accounted for by differences in maternal or neonatal demographic characteristics, bed occupancy rates, or a higher incidence of culture-proven nosocomial bacterial or fungal infections. Although the incidence of NEC was significantly higher at Center A, the percentage of patients with NEC transferred to the children's hospital for surgical evaluation and treatment was similar. The mortality rate of patients who developed NEC was similar among the three hospitals. Centers B and C utilize standardized feeding guidelines. During each of the 4-year study periods, one of three NICUs within the same health-care system had a higher incidence of NEC than the other two. Once NEC developed, the outcome was similar in all three NICUs. The higher incidence in Center A could not be explained by differences in demographics, socioeconomics, or systemic nosocomial infections. Similarities in feeding practices between Centers B and C suggest to us that these may be responsible, at least in part, for the differences in the incidence of NEC. Changing the feeding practices at Center A to those at Centers B and C is planned to test this theory.

KEYWORDS

Necrotizing enterocolitis - feeding practices - standardized feeding regimen

REFERENCES

• 1 Lemons J A, Bauer C R, Oh W et al.. Very low birth weight outcomes of the National Institute of Child Health and Human Development neonatal research network, January 1995 through December 1996. NICHD Neonatal Research Network.  Pediatrics. 2001;  107 E1-E8
• 2 Horbar J D, Badger G J, Carpenter J H et al.. Trends in mortality and morbidity for very low birth weight infants 1991-1999.  Pediatrics. 2002;  110(Pt1) 143-151
• 3 Stoll B J. The epidemiology of necrotizing enterocolitis.  Clin Perinatol. 1994;  21 205-218
• 4 Uauy R D, Fanaroff A A, Korones S B, Phillips E A, Philips J B, Wright L L. Necrotizing enterocolitis in very low birth weight infants: biodemographic and clinical correlates. National Institute of Child Health and Human Development Neonatal Research Network.  J Pediatr. 1991;  119 630-638
• 5 Kuzma-O'Reilly B, Duenas M L, Greecher C et al.. Evaluation, development, and implementation of potentially better practices in neonatal intensive care nutrition.  Pediatrics. 2003;  111(4) e461-e470
• 6 Bell M J, Ternberg J L, Feigin R D et al.. Neonatal necrotizing enterocolitis: therapeutic decision based upon clinical staging.  Ann Surg. 1978;  187 1-7
• 7 Walsh M C, Kliegman R M. Necrotizing enterocolitis: treatment based on staging criteria.  Pediatr Clin North Am. 1986;  33 179-201
• 8 Vermont Oxford Network Database .Manual of Operations. Release 10.0 2005: pp 77, 78
• 9 Street J L, Montgomery D, Alder S C, Lambert D K, Gerstmann D R, Christensen R D. Implementing feeding guidelines for NICU patients < 2000 g results in less variability in nutrition outcomes.  JPEN J Parenter Enteral Nutr. 2006;  30(6) 515-518
• 10 Neu J. Neonatal necrotizing enterocolitis: an update.  Acta Paediatr Suppl. 2005;  94(S449) 100-105
• 11 Luig M, Lui K. NSW & ACT NICUS Group . Epidemiology of necrotizing enterocolitis-Part II: Risks and susceptibility of premature infants during the surfactant era: a regional study.  J Paediatr Child Health. 2005;  41(4) 174-179
• 12 Kliegman R M, Fanaroff A A. Necrotizing enterocolitis.  N Engl J Med. 1984;  310 1093-1103
• 13 La Gamma E F, Browne L E. Feeding practices for infants weighing less than 1500 g at birth and the pathogenesis of necrotizing enterocolitis.  Clin Perinatol. 1994;  21 271-306
• 14 Patole S K, de Klerk N. Impact of standardised feeding regimens on incidence of neonatal necrotising enterocolitis: a systematic review and meta-analysis of observational studies.  Arch Dis Child Fetal Neonatal Ed. 2005;  90 F147-F151
• 15 Lucas A, Cole T J. Breast milk and necrotizing enterocolitis.  Lancet. 1990;  336 1519-1523
• 16 Schanler R J, Shulman R J, Lau C. Feeding strategies for premature infants: beneficial outcomes of feeding fortified human milk versus preterm formula.  Pediatrics. 1999;  103 1150-1157
• 17 Kamitsuka M D, Horton M K, Williams M A. The incidence of necrotizing enterocolitis after introducing standardized feeding schedules for infants between 1250 and 2500 grams and less than 35 weeks of gestation.  Pediatrics. 2000;  105 379-384
• 18 Caplan M S, Am M, Jilling T. The role of human milk in necrotizing enterocolitis.  Adv Exp Med Biol. 2002;  503 83-90
• 19 McGuire W, Anthony M Y. Donor human milk versus formula for preventing necrotising enterocolitis in preterm infants: systematic review.  Arch Dis Child Fetal Neonatal Ed. 2003;  88 F11-F14
• 20 Schanler R J, Lau C, Hurst N M, Smith E O. Randomized trial of donor human milk versus preterm formula as substitutes for mothers' own milk in the feeding of extremely premature infants.  Pediatrics. 2005;  116 400-406
• 21 Fanaroff A A, Hack M, Walsh M C. The NICHD Neonatal Research Network: changes in practice and outcomes during the first 15 years.  Semin Perinatol. 2003;  4 281-287
• 22 Hintz S R, Kendrick D E, Stoll B J et al.. Neurodevelopmental and growth outcomes of extremely low birth weight infants after necrotizing enterocolitis. NICHD Neonatal Research Network.  Pediatrics. 2005;  115 696-703