Increased incidence of necrotizing enterocolitis in the Netherlands after implementation of the new Dutch guideline for active treatment in extremely preterm infants: Results from three academic referral centers.

INTRODUCTION: Necrotizing enterocolitis (NEC) is a severe inflammatory disease, mostly occurring in preterm infants. The Dutch guidelines for active treatment of extremely preterm infants changed in 2006 from 26+0 to 25+0weeks of gestation, and in 2010 to 24+0 of gestation. We aimed to gain insight into the incidence, clinical outcomes and treatment strategies, in three academic referral centers in the Netherlands over the last nine years.

METHODS: We performed a multicenter retrospective cohort study of all patients with NEC (Bell stage ≥2a) in three academic referral centers diagnosed between 2005 and 2013. Outcome measures consisted of incidence, changes in clinical presentation, treatment strategies and mortality.

RESULTS: Between 2005 and 2013 14,161 children were admitted to the neonatal intensive care unit in the three centers. The overall percentage of children born at a gestational age of 24weeks and 25weeks increased with 1.7% after the introduction of the guidelines in 2006 and 2010. The incidence of NEC increased significantly (period 2005-2007: 2.1%; period 2008-2010 3.9%; period 2011-2013: 3.4%; P=0.001). We observed a significant decrease of peritoneal drainages (↓16%; P=0.001) and a decrease of laparotomies (↓24%; P=0.002). The mortality rate (33% in 2011-2013) remained unchanged.

CONCLUSION: The incidence of NEC significantly increased in the last nine years. The increase in incidence of NEC seemed to be related to an increase in infants born at a gestational age of 24 and 25weeks. The percentage of patients needing surgery decreased, while 30-day mortality did not change.

LEVEL OF EVIDENCE: Level IV.