Risk stratification for adverse economic outcomes in cardiac surgery

Recent emphasis on cost-containment in the health-care environment has focused attention on the cost of medical procedures. Selection of the appropriate treatment for coronary artery disease is of increasing concern. Coronary artery bypass grafting is common and very expensive, and this procedure will continue to be examined closely by reimbursement systems, particularly with regard to the lower initial cost of coronary angioplasty as a competing therapy.

Duke University Medical Center has a sophisticated accounting system that enables individual cost components to be identified, facilitates prospective analysis of cost/benefit, and aids allocation of limited hospital resources. In 1996, 1,114 coronary artery bypass procedures were performed at Duke. Preoperative patient characteristics were also analyzed in an attempt to predict risk factors for increased cost.

The median cost for these procedures was $20,682, excluding professional fees. Sixty percent of the costs were directly associated with patient care, and the other 40% were accounted for by indirect costs to support patient care. The most significant preoperative predictor of increased postoperative cost was the mortality estimate. If this variable was excluded from the analysis, other variables (for example, ejection fraction, age, identity of the surgeon, and congestive heart failure) were all related to increased costs.

Predicting costs based on preoperative variables offers the potential to reduce total costs through case-management strategies and aids in negotiating a risk-shared contract. However, cost reduction in routine care will have more financial impact than cost reduction by patient selection.