title: The effects of patient volume and level of care at the hospital of birth on neonatal mortality.
abstract: OBJECTIVE
  To examine the effects of neonatal intensive care unit (NICU) patient volume and the level of NICU care available at the hospital of birth on neonatal mortality.
  
  
  METHODS
  Birth certificate data linked to infant death certificates and to infant discharge abstracts were used in a logistic regression model to control for differences in each patient's clinical and demographic risks. Hospitals were classified by the level of NICU care available (no NICU: level I; intermediate NICU: level II; expanded intermediate NICU: level II+: tertiary NICU: level III) and by the average patient census in the NICU.
  
  
  METHODS
  All nonfederal hospitals in California with maternity services.
  
  
  METHODS
  All births in nonfederal hospitals in California in 1990 (N=594104), 473209 (singletons only) of which were successfully linked with discharge abstracts. Of these infants, 53229 were classified as likely NICU admissions.
  
  
  METHODS
  Death within the first 28 days of life, or within the first year of life, if continuously hospitalized.
  
  
  RESULTS
  Patient volume and level of NICU care at the hospital of birth both had significant effects on mortality. Compared with hospitals without an NICU, infants born in a hospital with a level III NICU with an average NICU census of at least 15 patients per day had significantly lower risk-adjusted neonatal mortality (odds ratio, 0.62; 95% confidence interval, 0.47-0.82; P=.002). Risk-adjusted neonatal mortality for infants born in smaller level III NICUs, and in level II+ and level II NICUs, regardless of size, was not significantly different from hospitals without an NICU, and was significantly higher than hospitals with large level III NICUS.
  
  
  CONCLUSIONS
  Risk-adjusted neonatal mortality was significantly lower for births that occurred in hospitals with large (average census, >15 patients per day) level III NICUs. Despite the differences in outcomes, costs for the birth of infants born at hospitals with large level III NICUs were not more than those for infants born at other hospitals with NICUs. Concentration of high-risk deliveries in urban areas in a smaller number of hospitals that could provide level III NICU care has the potential to decrease neonatal mortality without increasing costs.
authors.affiliation: Health Services Research and Development Center for Health Care Evaluation, VA Medical Center, Menlo Park, CA 94025, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Phibbs
authors.forename: J M
authors.initials: JM
authors.lastname: Bronstein
authors.forename: E
authors.initials: E
authors.lastname: Buxton
authors.forename: R H
authors.initials: RH
authors.lastname: Phibbs
mesh_terms: D002140:California / Q000453:epidemiology; D006297:Health Services Accessibility; D006301:Health Services Needs and Demand; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data*; D015931:Intensive Care, Neonatal; D016015:Logistic Models; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care; D010343:Patient Admission / Q000706:statistics & numerical data*; D012107:Research Design