title: Outborns or Inborns: Where Are the Differences? A Comparison Study of Very Preterm Neonatal Intensive Care Unit Infants Cared for in Australia and New Zealand and in Canada.
abstract: BACKGROUND
  Very preterm infants born outside tertiary centers are at higher risks of adverse outcomes than inborn infants. Regionalization of perinatal care has been introduced worldwide to improve outcomes.
  
  
  OBJECTIVE
  To compare the risk-adjusted outcomes of both inborn and outborn infants cared for in tertiary neonatal intensive care units in Australia and New Zealand and in Canada.
  
  
  METHODS
  Deidentified data of infants <32 weeks' gestational age from the 29 Australian and New Zealand Neonatal Network units (ANZNN; n = 9,893) and 26 Canadian Neonatal Network units (CNN; n = 7,133) between 2005 and 2007 were analyzed for predischarge adverse outcomes.
  
  
  RESULTS
  ANZNN had lower rates of outborns compared to CNN (13 vs. 19%), particularly of late admissions (>2 days of age; 5.8 vs. 22.2% of outborns) who had high morbidity rates. After adjusting for confounding variables including gestation, ANZNN inborn infants had lower odds of chronic lung disease [CLD; 17.0 vs. 23.3%; adjusted odds ratio (AOR) = 0.70, 95% CI: 0.64-0.77], severe neurological injuries on ultrasound (SNI; 4.1 vs. 6.7%; AOR = 0.62, 95% CI: 0.53-0.73), severe retinopathy (5.6 vs. 7%; AOR = 0.71, 95% CI: 0.59-0.84) and necrotizing enterocolitis (3.5 vs. 5.4%; AOR = 0.67, 95% CI: 0.56-0.79), but no difference in mortality odds. After excluding the late outborn admissions, ANZNN outborns had lower odds of SNI (AOR = 0.43, 95% CI: 0.32-0.58) and CLD (AOR = 0.63, 95% CI: 0.49-0.81) than CNN.
  
  
  CONCLUSIONS
  ANZNN inborn and early admitted outborn infants had lower odds of neonatal morbidities than their CNN counterparts. However, compared to ANZNN, the higher CNN rates of outborns and their late admissions are likely related to the differences in regionalization and referral practices, and may explain differences in outcomes.
authors.affiliation: School of Women's and Children's Health, Faculty of Medicine, University of New South Wales, Sydney, N.S.W., Australia.
authors.forename: Sadia
authors.initials: S
authors.lastname: Hossain
authors.forename: Prakesh S
authors.initials: PS
authors.lastname: Shah
authors.forename: Xiang Y
authors.initials: XY
authors.lastname: Ye
authors.forename: Brian A
authors.initials: BA
authors.lastname: Darlow
authors.forename: Shoo K
authors.initials: SK
authors.lastname: Lee
authors.forename: Kei
authors.initials: K
authors.lastname: Lui
mesh_terms: D001315:Australia; D002170:Canada; D005260:Female; D005865:Gestational Age; D006801:Humans; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology*; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data*; D016015:Logistic Models; D008297:Male; D009017:Morbidity; D015999:Multivariate Analysis; D009520:New Zealand; D016017:Odds Ratio; D018743:Perinatal Care; D062606:Tertiary Care Centers / Q000706:statistics & numerical data*