title: Surgical ligation of patent ductus arteriosus in premature infants: trends and practice variation.
abstract: OBJECTIVE
  We sought to analyse the variation in the incidence of patent ductus arteriosus over three recent time points and characterise ductal ligation practices in preterm infants in the United States, adjusting for demographic and morbidity factors.
  
  
  METHODS
  Using the Kids' Inpatient Database from 2003, 2006, and 2009, we identified infants born at ⩽32 weeks of gestation with International Classification of Diseases, Ninth Revision diagnosis of patent ductus arteriosus and ligation code. We examined patient and hospital characteristics and identified patient and hospital variables associated with ligation.
  
  
  RESULTS
  Of 182,610 preterm births, 30,714 discharges included a patent ductus arteriosus diagnosis. The rate of patent ductus arteriosus diagnosis increased from 14% in 2003 to 21% in 2009 (p<0.001). A total of 4181 ligations were performed, with an overall ligation rate of 14%. Ligation rate in infants born at ⩽28 weeks of gestation was 20% overall, increasing from 18% in 2003 to 21% in 2009 (p<0.001). The ligation rate varied by state (4-28%), and ligation was associated with earlier gestational age, associated diagnoses, hospital type, teaching hospital status, and region (p<0.001).
  
  
  CONCLUSIONS
  The rates of patent ductus arteriosus diagnosis and ligation have increased in the recent years. Variation exists in the practice of patent ductus arteriosus ligation and is influenced by patient and non-patient factors.
authors.affiliation: 1National Heart, Lung and Blood Institute,National Institutes of Health,Bethesda,Maryland,United States of America.
authors.forename: Jacqueline G
authors.initials: JG
authors.lastname: Weinberg
authors.affiliation: 1National Heart, Lung and Blood Institute,National Institutes of Health,Bethesda,Maryland,United States of America.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Evans
authors.affiliation: 1National Heart, Lung and Blood Institute,National Institutes of Health,Bethesda,Maryland,United States of America.
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Burns
authors.affiliation: 1National Heart, Lung and Blood Institute,National Institutes of Health,Bethesda,Maryland,United States of America.
authors.forename: Gail D
authors.initials: GD
authors.lastname: Pearson
authors.affiliation: 1National Heart, Lung and Blood Institute,National Institutes of Health,Bethesda,Maryland,United States of America.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Kaltman
mesh_terms: D016208:Databases, Factual; D003710:Demography; D004374:Ductus Arteriosus, Patent / Q000453:epidemiology* / Q000601:surgery*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D008026:Ligation / Q000706:statistics & numerical data* / Q000639:trends*; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D014481:United States / Q000453:epidemiology
keywords: Patent ductus arteriosus; neonate; preterm infant; surgical ligation