title: Representativeness of enrollment into a perinatal research repository.
abstract: OBJECTIVE
  To describe enrollment and compare demographic and clinical characteristics of neonates enrolled in the perinatal research repository (PRR) with eligible, but non-enrolled neonates.
  
  
  METHODS
  Characteristics from enrolled infants were compared with eligible, but non-enrolled infants using t-tests, Wilcoxon rank tests and χ(2) tests.
  
  
  RESULTS
  Between 1 January 2010 and 31 December 2011, 622 infants admitted to the neonatal intensive care unit (NICU), born < 37 weeks were screened for the PRR were eligible for enrollment. Of these, 233 enrolled in the study. There were no significant differences between enrolled and non-enrolled infants with regard to race, birth weight, gestational age and Apgar scores. Enrolled patients had a significantly longer length of stay [mean (standard deviation) = 55.0 (58.9) versus 38.0 (45.8) days; p < 0.01]. Mortality was significantly greater in the non-enrolled group (11.7 versus 3.0%; p < 0.01). Both groups had a similar total number of diagnoses [mean (standard deviation) = 5.7 (3.1) versus 5.8 (3.2)]; however, among survivors enrolled infants had slightly lower prevalence of hypoxic ischemic encephalopathy (0.0 versus 2.9%; p < 0.01) and seizures (1.8 versus 6.4%; p < 0.01). There were no significant differences in enrollment by prevalence of other morbidities.
  
  
  CONCLUSIONS
  These results suggest that a specimen collecting repository can enroll a sufficiently representative sample of eligible patients.
authors.affiliation: a Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital , Columbus , OH , USA .
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Moorehead
authors.forename: Mark
authors.initials: M
authors.lastname: Klebanoff
authors.forename: Leif D
authors.initials: LD
authors.lastname: Nelin
authors.forename: Reena
authors.initials: R
authors.lastname: Oza-Frank
mesh_terms: D035843:Biomedical Research / Q000379:methods*; D002648:Child; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D007902:Length of Stay; D008297:Male; D018579:Patient Selection; D054238:Perinatal Mortality; D010500:Perinatology; D011247:Pregnancy
keywords: Neonatal intensive care unit; perinatal repository; representative sample; research repository; study recruitment