title: Variations in definitions of mortality have little influence on neonatal intensive care unit performance ratings.
abstract: OBJECTIVE
  To measure the influence of varying mortality time frames on performance rankings among regional neonatal intensive care units (NICUs) in a large state.
  
  
  METHODS
  We performed a cross-sectional data analysis of very low birth weight infants receiving care at 24 level 3 NICUs. We tested the effect of 4 definitions of mortality: (1) death between admission and end of birth hospitalization or up to 366 days; (2) death between 12 hours of age and the end of birth hospitalization or up to 366 days; (3) death between admission and 28 days; and (4) death between 12 hours of age and 28 days. NICUs were ranked by quantifying their deviation from risk-adjusted expected mortality and dividing them into 3 tiers: top 6, bottom 6, and in between.
  
  
  RESULTS
  There was wide interinstitutional variation in risk-adjusted mortality for each definition (observed minus expected z-score range, -6.08 to 3.75). However, mortality-based NICU rankings and classification into performance tiers were very similar for all institutions in each of our time frames. Among all 4 definitions, NICU rank correlations were high (>0.91). Few NICUs changed relative to a neighboring tier with changes in definitions, and none changed by more than one tier.
  
  
  CONCLUSIONS
  The time frame used to ascertain mortality had little effect on comparative NICU performance.
authors.affiliation: Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX, USA. profit@bcm.edu
authors.forename: Jochen
authors.initials: J
authors.lastname: Profit
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Gould
authors.forename: David
authors.initials: D
authors.lastname: Draper
authors.forename: John A F
authors.initials: JA
authors.lastname: Zupancic
authors.forename: Marc A
authors.initials: MA
authors.lastname: Kowalkowski
authors.forename: LeChauncy
authors.initials: L
authors.lastname: Woodard
authors.forename: Kenneth
authors.initials: K
authors.lastname: Pietz
authors.forename: Laura A
authors.initials: LA
authors.lastname: Petersen
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D007363:Intensive Care Units, Neonatal / Q000592:standards*; D008297:Male; D011787:Quality of Health Care / Q000592:standards*; D009626:Terminology as Topic