PREDICTING OPERATIVE RISK FOR CORONARY-ARTERY SURGERY IN THE UNITED-KINGDOM - A COMPARISON OF VARIOUS RISK PREDICTION ALGORITHMS

Objective-To compare the ability of four risk models to predict operat ive mortality after coronary artery bypass graft surgery (CABG) in the United Kingdom.Design-Prospective study. Setting-Two cardiothoracic c entres in the United Kingdom. Subjects-1774 patients having CABG. Main outcome measures-Risk factors were recorded for all patients, along w ith in-hospital mortality. Predicted mortality was derived from the Am erican Society of Thoracic Surgeons (STS) risk program, Ontario Provin ce risk score (PACCN), Parsonnet score, and the UK Society of Cardioth oracic Surgeons risk algorithm. Results-There were significant differe nces (p < 0.05) between the British and American populations from whic h the STS risk algorithm was derived with respect to most variables. T he observed mortality in the British population was 3.7% (65 of 1774). The mean predicted mortality by STS score, PACCN, Parsonnet score, an d UK algorithms were 1.1%, 1.6%, 4.6%, and 4.7% respectively. The over all predictive ability of the models as measured by the area under the receiver operating characteristic curve were 0.65, 0.60, 0.73, and 0. 75, respectively. Conclusions-There are differences between the Britis h and American populations for CABG and the North American algorithms are not useful for predicting mortality in the United Kingdom. The UK Society of Cardiothoracic Surgeons algorithm, is the best of the model s tested but still only has limited predictive ability. Great care mus t be exercised when using methods of this type for comparisons of unit s and surgeons.