title: Level and volume of neonatal intensive care and mortality in very-low-birth-weight infants.
abstract: BACKGROUND
  There has been a large increase in both the number of neonatal intensive care units (NICUs) in community hospitals and the complexity of the cases treated in these units. We examined differences in neonatal mortality among infants with very low birth weight (below 1500 g) among NICUs with various levels of care and different volumes of very-low-birth-weight infants.
  
  
  METHODS
  We linked birth certificates, hospital discharge abstracts (including interhospital transfers), and fetal and infant death certificates to assess neonatal mortality rates among 48,237 very-low-birth-weight infants who were born in California hospitals between 1991 and 2000.
  
  
  RESULTS
  Mortality rates among very-low-birth-weight infants varied according to both the volume of patients and the level of care at the delivery hospital. The effect of volume also varied according to the level of care. As compared with a high level of care and a high volume of very-low-birth-weight infants (more than 100 per year), lower levels of care and lower volumes (except for those of two small groups of hospitals) were associated with significantly higher odds ratios for death, ranging from 1.19 (95% confidence interval [CI], 1.04 to 1.37) to 2.72 (95% CI, 2.37 to 3.12). Less than one quarter of very-low-birth-weight deliveries occurred in facilities with NICUs that offered a high level of care and had a high volume, but 92% of very-low-birth-weight deliveries occurred in urban areas with more than 100 such deliveries.
  
  
  CONCLUSIONS
  Mortality among very-low-birth-weight infants was lowest for deliveries that occurred in hospitals with NICUs that had both a high level of care and a high volume of such patients. Our results suggest that increased use of such facilities might reduce mortality among very-low-birth-weight infants.
authors.affiliation: Health Economics Resource Center and the Center for Health Care Evaluation, Veterans Affairs Palo Alto Health Care System, Menlo Park, CA 94025, USA. cphibbs@stanford.edu
authors.forename: Ciaran S
authors.initials: CS
authors.lastname: Phibbs
authors.forename: Laurence C
authors.initials: LC
authors.lastname: Baker
authors.forename: Aaron B
authors.initials: AB
authors.lastname: Caughey
authors.forename: Beate
authors.initials: B
authors.lastname: Danielsen
authors.forename: Susan K
authors.initials: SK
authors.lastname: Schmitt
authors.forename: Roderic H
authors.initials: RH
authors.lastname: Phibbs
mesh_terms: D002140:California / Q000453:epidemiology; D005260:Female; D005313:Fetal Death / Q000453:epidemiology; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data*; D015931:Intensive Care, Neonatal / Q000706:statistics & numerical data; D008297:Male; D016017:Odds Ratio