title: Individual and center-level factors affecting mortality among extremely low birth weight infants.
abstract: OBJECTIVE
  To examine factors affecting center differences in mortality for extremely low birth weight (ELBW) infants.
  
  
  METHODS
  We analyzed data for 5418 ELBW infants born at 16 Neonatal Research Network centers during 2006-2009. The primary outcomes of early mortality (≤12 hours after birth) and in-hospital mortality were assessed by using multilevel hierarchical models. Models were developed to investigate associations of center rates of selected interventions with mortality while adjusting for patient-level risk factors. These analyses were performed for all gestational ages (GAs) and separately for GAs <25 weeks and ≥25 weeks.
  
  
  RESULTS
  Early and in-hospital mortality rates among centers were 5% to 36% and 11% to 53% for all GAs, 13% to 73% and 28% to 90% for GAs <25 weeks, and 1% to 11% and 7% to 26% for GAs ≥25 weeks, respectively. Center intervention rates significantly predicted both early and in-hospital mortality for infants <25 weeks. For infants ≥25 weeks, intervention rates did not predict mortality. The variance in mortality among centers was significant for all GAs and outcomes. Center use of interventions and patient risk factors explained some but not all of the center variation in mortality rates.
  
  
  CONCLUSIONS
  Center intervention rates explain a portion of the center variation in mortality, especially for infants born at <25 weeks' GA. This finding suggests that deaths may be prevented by standardizing care for very early GA infants. However, differences in patient characteristics and center intervention rates do not account for all of the observed variability in mortality; and for infants with GA ≥25 weeks these differences account for only a small part of the variation in mortality.
authors.affiliation: Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA.
authors.forename: Brandon W
authors.initials: BW
authors.lastname: Alleman
authors.forename: Edward F
authors.initials: EF
authors.lastname: Bell
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: John M
authors.initials: JM
authors.lastname: Dagle
authors.forename: P Brian
authors.initials: PB
authors.lastname: Smith
authors.forename: Namasivayam
authors.initials: N
authors.lastname: Ambalavanan
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Laughon
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Stoll
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Goldberg
authors.forename: Waldemar A
authors.initials: WA
authors.lastname: Carlo
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Murray
authors.forename: C Michael
authors.initials: CM
authors.lastname: Cotten
authors.forename: Seetha
authors.initials: S
authors.lastname: Shankaran
authors.forename: Michele C
authors.initials: MC
authors.lastname: Walsh
authors.forename: Abbot R
authors.initials: AR
authors.lastname: Laptook
authors.forename: Dan L
authors.initials: DL
authors.lastname: Ellsbury
authors.forename: Ellen C
authors.initials: EC
authors.lastname: Hale
authors.forename: Nancy S
authors.initials: NS
authors.lastname: Newman
authors.forename: Dennis D
authors.initials: DD
authors.lastname: Wallace
authors.forename: Abhik
authors.initials: A
authors.lastname: Das
authors.forename: Rosemary D
authors.initials: RD
authors.lastname: Higgins
mesh_terms: D002423:Cause of Death; D005260:Female; D005865:Gestational Age; D017052:Hospital Mortality; D006785:Hospitals, University / Q000706:statistics & numerical data*; D006801:Humans; D052577:Infant, Extremely Low Birth Weight; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000401:mortality* / Q000628:therapy; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data*; D008297:Male; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D012042:Registries / Q000706:statistics & numerical data; D012307:Risk Factors; D014481:United States
keywords: NICU; extremely preterm infants; mortality rates; outcome; preterm infants