title: Critical appraisal of the role of Ureaplasma in the development of bronchopulmonary dysplasia with metaanalytic techniques.
abstract: BACKGROUND
  Controversy exists over whether or not Ureaplasma colonization or infection of the respiratory tract contributes to the development of bronchopulmonary dysplasia (BPD). Because BPD is a major cause of morbidity and mortality in preterm infants and a potential therapeutic intervention with antimicrobials is possible, we sought to evaluate and critique the current medical literature and to document the reported association between Ureaplasma and BPD.
  
  
  METHODS
  We analyzed all peer-reviewed articles and previous reviews including cross-references that reported Ureaplasma respiratory tract colonization or infection and development of BPD in neonates published from January 1966 to December 2004. Inclusion criteria included a cohort limited to all neonatal intensive care unit admissions or all colonized infants, articles that did not define a numerator and a denominator for BPD and Ureaplasma or that included patients from other reports were excluded from the analysis. We evaluated BPD at 28 postnatal days (BPD28) or 36 weeks post-menstrual age (BPD36).
  
  
  RESULTS
  Twenty-three studies with an aggregate of 2216 infants reported BPD28, and 8 studies with 751 infants reported BPD36. Although there was significant association between Ureaplasma colonization and both BPD28 and BPD36, there was substantial heterogeneity (Q test statistic, P < 0.01). We therefore focused on describing the study characteristics associated with an increased relative proportion of BPD. The greatest contribution to effect was from the studies enrolling fewer than 100 infants.
  
  
  CONCLUSIONS
  Ureaplasma colonization is associated with higher reported rates of BPD, but the greatest reported effect is seen in small studies; reporting bias may be partially responsible for this effect.
authors.affiliation: Department of Pediatrics. University of Alabama at Birmingham, Birmingham, AL, USA. rschelonka@peds.uab.edu
authors.forename: Robert L
authors.initials: RL
authors.lastname: Schelonka
authors.forename: Brenda
authors.initials: B
authors.lastname: Katz
authors.forename: Ken B
authors.initials: KB
authors.lastname: Waites
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Benjamin
mesh_terms: D001997:Bronchopulmonary Dysplasia / Q000382:microbiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000382:microbiology*; D007363:Intensive Care Units, Neonatal; D012137:Respiratory System / Q000382:microbiology*; D014509:Ureaplasma / Q000302:isolation & purification*; D016869:Ureaplasma Infections / Q000150:complications* / Q000382:microbiology