title: Epidemiologic Trends in Neonatal Intensive Care, 2007-2012.
abstract: OBJECTIVE
  Neonatal intensive care has been highly effective at improving newborn outcomes but is expensive and carries inherent risks. Existing studies of neonatal intensive care have focused on specific subsets of newborns and lack a population-based perspective.
  
  
  OBJECTIVE
  To describe admission rates to neonatal intensive care units (NICUs) for US newborns across the entire continuum of birth weight and how these rates have changed across time, as well as describe the characteristics of infants admitted to NICUs.
  
  
  METHODS
  An epidemiologic time-trend analysis was conducted on April 1, 2015, of live births (≥500 g) from January 1, 2007, to December 31, 2012, to residents of 38 US states and the District of Columbia, recorded using the 2003 revision of the US Standard Certificate of Live Birth (N = 17,896,048).
  
  
  METHODS
  Birth year.
  
  
  METHODS
  Crude, stratified (by birth weight), and adjusted admission rates. Trends in birth weight, gestational age, weight for gestational age, and use of assisted ventilation are presented to describe the cohort of admitted newborns.
  
  
  RESULTS
  In 2012, there were 43.0 NICU admissions per 1000 normal-birth-weight infants (2500-3999 g), while the admission rate for very low-birth-weight infants (<1500 g) was 844.1 per 1000 live births. Overall, admission rates during the 6-year study period increased from 64.0 to 77.9 per 1000 live births (relative rate, 1.22; 95% CI, 1.21-1.22 [P < .001]). Admission rates increased for all birth weight categories. Trends in relative rates adjusted for maternal and newborn characteristics showed a similar 23% increase (95% CI, 1.22-1.23 [P < .001]). During the study period, newborns admitted to a NICU were larger and less premature, although no consistent trend was seen in weight for gestational age or the use of assisted ventilation.
  
  
  CONCLUSIONS
  After adjustment for infant and maternal risk factors, US newborns at all birth weights are increasingly likely to be admitted to a NICU, which raises the possibility of overuse of neonatal intensive care in some newborns. Further study is needed into the causes of the increased use observed in our study as well as its implications for payers, policymakers, families, and newborns.
authors.affiliation: The Dartmouth Institute for Health Policy & Clinical Practice, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire.
authors.forename: Wade
authors.initials: W
authors.lastname: Harrison
authors.affiliation: The Dartmouth Institute for Health Policy & Clinical Practice, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire.
authors.forename: David
authors.initials: D
authors.lastname: Goodman
mesh_terms: D000293:Adolescent; D000328:Adult; D001724:Birth Weight; D005865:Gestational Age; D006760:Hospitalization / Q000706:statistics & numerical data / Q000639:trends; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data / Q000639:trends*; D015931:Intensive Care, Neonatal / Q000706:statistics & numerical data / Q000639:trends*; D012307:Risk Factors; D014481:United States; D055815:Young Adult