title: 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.
abstract: BACKGROUND
  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.
  
  
  CONCLUSIONS
  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.
  
  
  METHODS
  Level IV.
authors.affiliation: Department of Pediatric Surgery, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, The Netherlands. Electronic address: f.h.heida@umcg.nl.
authors.forename: Fardou H
authors.initials: FH
authors.lastname: Heida
authors.affiliation: Department of Pediatric Surgery, Pediatric Surgical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: Lisanne
authors.initials: L
authors.lastname: Stolwijk
authors.affiliation: Department of Pediatric Surgery, Pediatric Surgical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: Marie-Louise H J
authors.initials: MH
authors.lastname: Loos
authors.affiliation: Department of Pediatric Surgery, Pediatric Surgical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: Stannie J
authors.initials: SJ
authors.lastname: van den Ende
authors.affiliation: Department of Neonatology Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Wes
authors.initials: W
authors.lastname: Onland
authors.affiliation: Department of Neonatology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Frank A M
authors.initials: FA
authors.lastname: van den Dungen
authors.affiliation: Department of Neonatology, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, The Netherlands.
authors.forename: Elisabeth M W
authors.initials: EM
authors.lastname: Kooi
authors.affiliation: Department of Neonatology, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, The Netherlands.
authors.forename: Arend F
authors.initials: AF
authors.lastname: Bos
authors.affiliation: Department of Pediatric Surgery, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, The Netherlands.
authors.forename: Jan B F
authors.initials: JB
authors.lastname: Hulscher
authors.affiliation: Department of Pediatric Surgery, Pediatric Surgical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: Roel
authors.initials: R
authors.lastname: Bakx
mesh_terms: D000046:Academic Medical Centers; D020345:Enterocolitis, Necrotizing / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology / Q000628:therapy; D005260:Female; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology / Q000628:therapy; D015931:Intensive Care, Neonatal / Q000379:methods / Q000592:standards* / Q000706:statistics & numerical data / Q000639:trends; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D017410:Practice Guidelines as Topic; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data / Q000639:trends; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Incidence; Necrotizing enterocolitis; Netherlands