title: Platelet Counts and Patent Ductus Arteriosus in Preterm Infants: A Systematic Review and Meta-Analysis.
abstract: BACKGROUND
  Several cohort studies have shown an association between low platelet counts in the first day(s) of life and patent ductus arteriosus (PDA) in preterm infants. However, these results have not been confirmed by other studies.
  
  
  OBJECTIVE
  To perform a meta-analysis of all the studies addressing the relationship between platelet counts in the first day(s) of life and PDA in preterm infants.
  
  
  METHODS
  PubMed/MEDLINE and EMBASE were searched from their inception until December 2014. Results from 11 cohort studies involving 3,479 preterm infants (gestational age <32 weeks) were pooled using random-effects modeling.
  
  
  RESULTS
  Meta-analysis showed a significant positive association between PDA and platelet counts <150 × 10(9)/l [6 studies, risk ratio (RR) = 1.215, 95% CI: 1.027-1.436], between PDA and platelet counts <100 × 10(9)/l (5 studies, RR = 1.255, 95% CI: 1.034-1.525), and between significant PDA (SPDA) and platelet counts <100 × 10(9)/l (5 studies, RR = 1.254, 95% CI: 1.021-1.540). The association between SPDA and platelet counts <150 × 10(9)/l was not statistically significant (6 studies, RR = 1.289, 95% CI: 0.925-1.795). Pooled standard differences in mean platelet counts between infants with and without PDA/SPDA were not statistically different.
  
  
  CONCLUSIONS
  This meta-analysis reveals a marginal but significant association between low platelet counts in the first day(s) of life and PDA/SPDA in very preterm infants. This association needs to be confirmed in prospective studies.
authors.affiliation: Department of Pediatrics, Maastricht University Medical Center (MUMC+), School for Oncology and Developmental Biology (GROW) and Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands.
authors.forename: Sorina R
authors.initials: SR
authors.lastname: Simon
authors.forename: Lieke
authors.initials: L
authors.lastname: van Zogchel
authors.forename: Maria Pilar
authors.initials: MP
authors.lastname: Bas-Suárez
authors.forename: Giacomo
authors.initials: G
authors.lastname: Cavallaro
authors.forename: Ronald I
authors.initials: RI
authors.lastname: Clyman
authors.forename: Eduardo
authors.initials: E
authors.lastname: Villamor
mesh_terms: D004374:Ductus Arteriosus, Patent / Q000453:epidemiology*; D005865:Gestational Age; D006801:Humans; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D010976:Platelet Count; D012307:Risk Factors