title: Improvement in outcome for very low birthweight children: apparent or real?
abstract: OBJECTIVE
  To determine whether improvement in the survival rate of infants with a birthweight of less than 1501 g was accompanied by an increase in the rate of neurological impairment or disability among the survivors.
  
  
  METHODS
  Two cohorts of consecutive very low birthweight infants (birthweight less than 1501 g) in one tertiary perinatal centre were followed prospectively to eight years of age; for both cohorts, comparison groups of children of birthweight more than 1501 g were randomly selected from hospital births.
  
  
  METHODS
  The first cohort was born before the introduction of assisted ventilation (1966-1970), the second after assisted ventilation was well established (1980-1982).
  
  
  METHODS
  Comparisons between cohorts, at eight years of age, of the survival rates and the rates of severe sensorineural impairments and disabilities.
  
  
  RESULTS
  The survival rate for very low birthweight infants to eight years of age almost doubled between these cohorts, from 37.1% to 67.8% (odds ratio [OR], 3.4; 95% confidence interval [CI], 2.5-4.7; chi 2 = 57.6; P much less than 0.0001). The biggest gain was the increase in non-disabled survivors at eight years of age, from 52.6% in the first cohort to 80.8% in the second cohort (OR, 3.5; 95% CI, 2.2-5.7; chi 2 = 26.7; P less than 0.0001). Furthermore, the rate of severe disabilities in survivors fell substantially, from 13.6% to 4.1% (OR, 0.31; 95% CI, 0.14-0.69; chi 2 = 8.3; P less than 0.01). Of specific impairments, the rate of severe sensorineural deafness fell substantially (3.2% to 0%: OR, 0.14, 95% CI, 0.02-0.81; chi 2 = 4.8; P less than 0.05), as did the rate of severe intellectual impairment (13.0% to 2.7%: OR, 0.25; 95% CI, 0.11-0.57; chi 2 = 10.7; P less than 0.002). Only the rate of cerebral palsy increased, but not significantly (2.6% to 6.8%; OR, 2.6; 95% CI, 0.89-7.6; chi 2 = 3.0).
  
  
  CONCLUSIONS
  It has been possible to improve the survival rate of very low birthweight infants over time without increasing the number of severely disabled survivors. Whether the long-term outcome for these infants is continuing to improve with more recent advances in perinatal care remains to be determined.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Melbourne, Parkville, Vic.
authors.forename: W H
authors.initials: WH
authors.lastname: Kitchen
authors.forename: A L
authors.initials: AL
authors.lastname: Rickards
authors.forename: L W
authors.initials: LW
authors.lastname: Doyle
authors.forename: G W
authors.initials: GW
authors.lastname: Ford
authors.forename: E A
authors.initials: EA
authors.lastname: Kelly
authors.forename: C
authors.initials: C
authors.lastname: Callanan
mesh_terms: D002547:Cerebral Palsy / Q000453:epidemiology; D002648:Child; D002657:Child Development; D015331:Cohort Studies; D003638:Deafness / Q000453:epidemiology; D006233:Persons with Disabilities / Q000706:statistics & numerical data; D005500:Follow-Up Studies; D006771:Hospitals, Maternity / Q000706:statistics & numerical data; D006801:Humans; D007226:Infant Mortality; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000453:epidemiology; D015931:Intensive Care, Neonatal / Q000706:statistics & numerical data* / Q000639:trends; D009026:Mortality; D011446:Prospective Studies; D012121:Respiration, Artificial; D015996:Survival Rate; D016896:Treatment Outcome; D014739:Victoria