Prognostic value of a treadmill exercise score in outpatients with suspected coronary artery disease

Multiple regression analysis is a sophisticated statistical tool that has been applied to the study of many disease risk factors. However, the results are often too complex for routine use in the treatment of patients. Conversely, dividing patients into high- and low-risk groups is often too simplistic and erroneously implies that all patients within a group are comparable. A scoring technique has been devised to permit the evaluation of heart patients using the treadmill exercise test. Previous research has shown that different physiological variables measured during the treadmill test may be combined for an accurate prognosis of patients admitted to a hospital for work-up. This same test has now been evaluated for use with outpatients who are suspected of having coronary artery disease. A total of 613 patients were evaluated using the test and followed-up for a period of at least four years. The test, which is scored on a scale from -25 for the highest risk of disease to +15 for the lowest, proved to be even more reliable for outpatients than it had been for hospitalized patients. The test scores accurately indicated those patients who died during the follow-up period. Patients with scores better than +5 had a 99 percent survival for the 4-year period. The scoring procedure is presented in the form of a nomogram. This graphical device permits the evaluation of risk without the detailed mathematical calculations that would be necessary using regression. Using only a straightedge, measurements for chest pain, electrocardiographic abnormalities, and duration of exercise are connected. The intersection of the straight line with the prognosis scale directly yields the desired result. (Consumer Summary produced by Reliance Medical Information, Inc.)