Eastern Cardiothoracic Surgical Society

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Modifiable Inter-Hospital Cost Variability in Coronary Artery Bypass Surgery
Xun Zhou1, Clifford E. Fonner2, Alejandro Suarez-Pierre1, Cecillia Lui1, Diane Alejo1, Stefano Schena1, Michael Mazzeffi3, Glenn JR Whitman1, Bradley S. Taylor3, Niv Ad4, Rawn Salenger5.
1The Johns Hopkins University School of Medicine, Baltimore, MD, USA, 2Maryland Cardiac Surgery Quality Initiative, Baltimore, MD, USA, 3University of Maryland School of Medicine, Baltimore, MD, USA, 4Washington Adventist Hospital, Takoma Park, MD, USA, 5University of Maryland St. Joseph Medical Center, Towson, MD, USA.

OBJECTIVE: We sought to identify potentially modifiable sources of cost variability for coronary artery bypass grafting (CABG), to help control costs and improve quality.
METHODS: A retrospective database of CABG patients from 2012-2016 in Maryland was created by cross-linking clinical data from the Maryland Cardiac Surgery Quality Initiative and charge data from the Maryland Health Services Cost Review Commission. Charge data were normalized to calculate mean charges per unit resource utilized. We used multivariate linear regression to analyze effects of patient factors, postoperative complications, and operative factors on variability of cost.
RESULTS: After risk adjustment of all 10,540 patients, individual hospital remained an independent predictor of cost. In multivariate regression, the greatest driver of inter-hospital cost variability was excess rates of postoperative complications, particularly, stroke (+$60,014, p=0.005), prolonged ventilation (+$98,805, p<0.001), renal failure (+$173,335, p<0.001), and sepsis (+$276,932, p<0.001) (Figure1). Potentially modifiable patient factors contributing to cost variance included congestive heart failure (+$14,121, p<0.001), elevated hemoglobin A1c (+$1,177 per % A1c, p = 0.029), and Medicaid insurance (+$8,798, p = 0.002). Higher preoperative hematocrit was associated with decreased cost (-$581 per % hematocrit, p<0.001). Operative factors affecting cost variation included emergency surgery (+$36,728, p<0.001) and longer cardiopulmonary bypass (+$381 per minute, p<0.001). Decreased costs were associated with greater number of bypasses (-$17,585/bypass, p<0.001) and higher case volume ($670 /100 cases).
CONCLUSIONS: Cost for CABG varies based on hospital in our state. Standardizing to best practices may decrease postoperative complications and enhance pre-operative optimization, leading to higher quality and lower cost.


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