title: Association Between Extracorporeal Membrane Oxygenation Center Volume and Mortality Among Children With Heart Disease: Propensity and Risk Modeling.
abstract: OBJECTIVE
  To evaluate the relationship between extracorporeal membrane oxygenation center volume and mortality in children undergoing heart operations using propensity score matching in a multiinstitutional cohort.
  
  
  METHODS
  Post hoc analysis of data from an existing national database, Pediatric Health Information System. Propensity score matching was performed to 1-1-1 match patients in low-volume (0-30 cases per year), medium-volume (31-50 cases per year), and high-volume (> 50 cases per year) categories. We tested the sensitivity of our findings by repeating the primary analyses using traditional statistical techniques (traditional regression-based methods and covariate adjustment using propensity score).
  
  
  METHODS
  Forty-two children's hospitals across the Unites States.
  
  
  METHODS
  Patients 18 years old or younger receiving extracorporeal membrane oxygenation before or after pediatric heart operation at a Pediatric Health Information System participating hospital (2004-2013) were included.
  
  
  METHODS
  None.
  
  
  RESULTS
  A total of 3,502 from 42 hospitals qualified for inclusion. Using propensity score matching, 1,962 patients were matched 1-1-1 to compare the three volume categories (654 patients in each category). Overall mortality was 1,493 patients (43%). Before matching and adjustment, low- and medium-volume centers were associated with higher mortality (low versus high volume: unadjusted odds ratio, 1.99; 95% CI, 1.68-2.36; p < 0.001). After matching, there was no significant association between center volume and mortality in unadjusted and adjusted analyses (low versus high volume: unadjusted odds ratio, 1.06; 95% CI, 0.85-1.32; p = 0.62 and adjusted odds ratio, 0.97; 95% CI, 0.63-1.50; p = 0.90). This relationship remained similar for analyses using traditional statistical techniques (regression adjustment, low versus high volume: adjusted odds ratio, 1.23; 95% CI, 0.80-1.89; p = 0.35 and covariate adjustment using propensity score, low versus high volume: adjusted odds ratio, 1.16; 95% CI, 0.77-1.74; p = 0.49).
  
  
  CONCLUSIONS
  We demonstrated no relationship between extracorporeal membrane oxygenation center volume and mortality. Further analyses are needed to evaluate this relationship.
authors.affiliation: 1Division of Pediatrics, Department of Pediatrics, Cardiology, University of Arkansas for Medical Sciences, Little Rock, AR. 2Biostatistics Section, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR.
authors.forename: Punkaj
authors.initials: P
authors.lastname: Gupta
authors.forename: Mallikarjuna
authors.initials: M
authors.lastname: Rettiganti
mesh_terms: D000293:Adolescent; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass / Q000706:statistics & numerical data; D002648:Child; D002675:Child, Preschool; D015199:Extracorporeal Membrane Oxygenation / Q000706:statistics & numerical data*; D005260:Female; D006331:Heart Diseases / Q000151:congenital / Q000401:mortality* / Q000628:therapy*; D017052:Hospital Mortality; D061847:Hospitals, High-Volume / Q000706:statistics & numerical data*; D061846:Hospitals, Low-Volume / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007902:Length of Stay; D008297:Male; D015233:Models, Statistical; D057216:Propensity Score; D018570:Risk Assessment; D014481:United States / Q000453:epidemiology