PREOPERATIVE PREDICTORS OF COST IN MEDICARE-AGE PATIENTS UNDERGOING CORONARY-ARTERY BYPASS-GRAFTING

Background. Identification of preoperative factors that contribute to the cost of coronary artery bypass grafting could aid in predicting th e procedure's expense. In this study, 30 sociodemographic and clinical preoperative factors were examined with ''survival analysis'' techniq ues to determine characteristics related to total hospital cost. Metho ds. Characteristics of all patients age 65 or older undergoing isolate d coronary artery bypass grafting from July 1993 to April 1995 (n = 75 7) were recorded. Software was developed within the hospital's Transit ions Systems, inc, database to calculate the outcome variable of total cost. Nonparametric methods were used for the univariate analysis of the data, and the Cox proportional hazards model was used for the mult ivariable analysis, censoring 25 patients who died in the hospital. Re sults. Median hospital cost from the day of the operation until discha rge was $15,198. Median length of stay after the operation was 6 days. Multivariable analysis revealed that age, preoperative renal failure, history of cerebrovascular accident, low ejection fraction, and surgi cal urgency were independent predictors of total cost. Conclusions. Th is study, using an accurate representation of true hospital cost and a modeling technique that accounts far the confounding effect of in-hos pital death on cost, provides a template for analysis of cost in other patient groups. (Ann Thorac Surg 1998;66:740-6) (C) 1998 by The Socie ty of Thoracic Surgeons.