Identifying pre- and postoperative predictors of cost and length of stay for coronary artery bypass surgery.

Prior studies of resource use for coronary artery bypass graft (CABG) surgery have either focused on a limited number of hospitals or have used charges instead of costs. We used a large statewide database (n = 6791) to study predictors of cost and length of stay (LOS) for CABG surgery. We used linear regression to sequentially model (a) specific procedures performed, (b) preoperative patient characteristics, and (c) postoperative events to determine the relative impact of these 3 factors on resource use. We then used the resulting models to calculate adjusted mean hospital costs and LOS. These 3 factors were all significantly associated with resource use. Postoperative events were the greatest determinant of costs, while preoperative characteristics were the greatest determinant of LOS. Despite risk adjustment for these factors, resource use differed significantly across 12 hospitals (mean cost range, $22,200 to $41,900; mean LOS range, 11 to 18 days), suggesting that some institutions may need to reduce their resource use.