Determinants of costs and resource utilization associated with open heart surgery.

Abstract

This study sought to determine the patient- and the therapy-related determinants of in-hospital costs for patients undergoing heart surgery at the University Hospital in Zurich. We performed a retrospective analysis of all adult cardiac surgical patients from the canton St. Gallen who were covered by a fixed fee arrangement (29,500 Swiss francs (19,470 Euro)) and referred to our institution during 1998. A total of 201 patients (143 (71%) male) with basic insurance were hospitalized in 1998 under the fixed fee arrangement. The mean age of the patients was 61.4 years (95% confidence intervals (CI): 60; 63). With the help of univariate analysis, the following pre-operative characteristics were found to be significantly associated with cost: age (P<0.001), pre-operative cardiac diagnosis (coronary vs valvular heart disease) (P<0.001) and EuroSCORE (P<0.0001). A significant correlation was also found between intra-operative variables and costs (P<0.0001) as well as between postoperative variables and costs (P<0.0001). A linear regression model based on EuroSCORE, operation time and postoperative infection status is able to predict costs for patients (all P -values <0.0001, except for P<0.05 for operation time, R(2)=0.565). These results suggest that both pre-operative (patient related) and intra-operative (therapy- and patient-related) variables are predictors of costs in cardiac surgical patients.