title: Prediction of costs and length of stay in coronary artery bypass grafting.
abstract: BACKGROUND
  Although more than 200,000 bypass operations are performed in the United States annually, few data exist on the predictors of costs and resource use for this procedure. Questions related to clinical outcomes, costs, and resource use in coronary artery bypass grafting (CABG) were addressed.
  
  
  METHODS
  In a multiinstitutional statewide database, patient level data from 42,839 patients undergoing isolated CABG were combined with cost data. After adjustment for cost-to-charge ratios and inflation, the association of length of stay and costs with the Society of Thoracic Surgeons-Predicted Risk of Mortality (STS-PROM) was analyzed. Patients were randomly divided into development (60%) and validation (40%) cohorts. Regression models were developed to analyze the impact of patient characteristics, comorbidities, and adverse events on postoperative length of stay and total costs.
  
  
  RESULTS
  Postoperative length of stay and total direct costs for CABG averaged 6.9 days and $38,847. Length of stay and costs increased from 5.4 days and $33,275 in the lowest-risk decile (mean STS-PROM of 0.6%) to 13.8 days and $69,122 in the highest-risk decile (mean STS-PROM 19%). Compared with adverse events, patient characteristics had little impact on length of stay and costs. on validation, the models that combined preoperative and postoperative variables explained variance better (R(2) = 0.51 for length of stay; R(2) = 0.47 for costs) and were better calibrated than the preoperative models (R(2) = 0.10 for length of stay; R(2) = 0.14 for costs).
  
  
  CONCLUSIONS
  The STS-PROM and preoperative regression models are useful for preoperative prediction of costs and length of stay for groups of patients, case-mix adjustment in hospital benchmarking, and pay for performance measures. The combined preoperative and postoperative models identify incremental costs and length of stay associated with adverse events and are more suitable for prioritizing quality improvement efforts.
authors.affiliation: Department of Cardio-Thoracic Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Ruben L
authors.initials: RL
authors.lastname: Osnabrugge
authors.affiliation: Inova Heart and Vascular Institute, Fairfax, Virginia.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Speir
authors.affiliation: Department of Cardio-Thoracic Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Head
authors.affiliation: Saint Luke's Mid America Heart Institute, Kansas City, Missouri.
authors.forename: Philip G
authors.initials: PG
authors.lastname: Jones
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University of Virginia Health System, Charlottesville, Virginia.
authors.forename: Gorav
authors.initials: G
authors.lastname: Ailawadi
authors.affiliation: ARMUS Corporation, San Mateo, California; Virginia Cardiac Surgery Quality Initiative, Falls Church, Virginia.
authors.forename: Clifford E
authors.initials: CE
authors.lastname: Fonner
authors.affiliation: Virginia Cardiac Surgery Quality Initiative, Falls Church, Virginia.
authors.forename: Edwin
authors.initials: E
authors.lastname: Fonner
authors.affiliation: Department of Cardio-Thoracic Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: A Pieter
authors.initials: AP
authors.lastname: Kappetein
authors.affiliation: Mid-Atlantic Cardiothoracic Surgeons, Sentara Heart Hospital, Norfolk, Virginia. Electronic address: rich@macts.com.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Rich
mesh_terms: D000368:Aged; D001026:Coronary Artery Bypass / Q000191:economics*; D005260:Female; D017048:Health Care Costs; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis