General Papers 15

Abstract

Aims: Comparative surgical audit is increasingly important, although fraught due to the difficulty of risk adjusted analysis. The surgical risk score was developed to provide surgeon-independent risk-adjusted mortality in general surgery using readily available clinical indices (CEPOD grade of operative urgency, BUPA grade of operative magnitude and ASA grade of patient comorbidities). Methods: Prospective data collection from 4308 patients admitted under the care of three general surgeons (May 1997–October 1999) created an initial data set of 3144 procedures with 134 deaths. Each procedure was scored by summation of linear scales allocated to CEPOD, BUPA and ASA grades to devise a surgical risk scale (SRS) ranging from 3 to 14. Multi-variate logistic regression analysis involving the three variables and uni-variate analysis of the SRS scores were undertaken. Receiver operating characteristic and calibration curves were formulated. This process was validated on another data set (2780 patients) derived from all admissions to the same surgeons (November 1999–December 2000). Results: Uni-variate logistic analysis of the SRS score revealed it to be significantly predictive of death (β = 0.84, P < 0.001). The SRS score did not over predict mortality for low risk procedures. The areas under the receiver operating characteristic curve was 0.931 for the initial data set and 0.951 for the validation set. Conclusion: The SRS is easy to use, formulate and interpret. It has been validated as a tool for risk-adjusted comparative audit in a population of general surgical patients.