Estimation of surgical costs using a prediction scoring system - Estimation of physiologic ability and surgical stress

Hypothesis: Our predictive scoring system, Estimation of Physiologic Ability and Surgical Stress, can estimate surgical costs. Design: Multicenter cohort study for 1 year. Setting: Six national hospitals in Japan. Patients: A consecutive series of 929 patients who underwent elective gastrointestinal operations. Main Outcome Measures: The preoperative and the comprehensive risk scores of the Estimation of Physiologic Ability and Surgical Stress were determined preoperatively and immediately after the operation, respectively. Estimated costs were computed using the following equation: costs=US $10160+(US $13470 X comprehensive risk score). Data on length of stay, costs for surgical admission, and severity of postoperative complications were collected at hospital discharge. Results: The comprehensive risk score significantly correlated with the severity of the postoperative complications (Spearman rank correlation=0.54, P<.001), the length of stay (Spearman rank correlation=0.69, P<.001), and the costs (Spearman rank correlation= 0.72, P<001). The ratio of real to estimated costs varied from 0.82 to 1. 17 at the various ranges of the comprehensive risk score, resulting in 0.93 in the total 929 patients. This ratio varied from 0.71 to 1.12 among the hospitals, the smallest of which was attributed to the hospital that primarily used the clinical pathways. A significant increase in the costs was observed according to the preoperative risk score for open colectomy (P=.009) and distal gastrectomy (P=.002). When we simulated the hospital revenue where different payment rates were set according to the preoperative risk score, the revenue seemed to, improve in the hospitals that treated more high-risk patients, compared with the fixed payment system. Conclusion: The Estimation of Physiologic Ability and Surgical Stress scoring system may be useful for estimating surgical costs, making a benchmark analysis, and determining the rate in a risk-based payment system.