CLINICAL-YIELD AND COST OF EXERCISE TREADMILL TESTING TO SCREEN FOR CORONARY-ARTERY DISEASE IN ASYMPTOMATIC ADULTS

Exercise treadmill testing is frequently performed to screen for coron ary artery disease (CAD) in asymptomatic individuals; however, its cli nical value is unclear. We examined a consecutive cohort of asymptomat ic adults undergoing exercise treadmill testing at the Cleveland Clini c Foundation between September 1990 and December 1993. End points incl uded (1) identification of subjects with severe CAD and (2) performanc e of any second diagnostic study within 90 days of the index exercise treadmill test. Screening exercise treadmill testing was performed in 4,334 adults (median age 51, 89% men); only 34% had greater than or eq ual to 1 cardiac risk factor and 15% exhibited an abnormal response to exercise. A second test after treadmill testing was performed in 215 patients (in 110, coronary angiography; in 105, stress thallium scinti graphy, followed by coronary angiography in 16). The strongest predict or of referral for a second test was an ischemic ST-segment response ( adjusted odds ratio [OR] 34, 95% confidence intervals [CI] 24 to 47, p <0.0001). The only clinical variable independently associated with re ferral for a second test was female gender (adjusted OR 0.35, 95% CI 0 .21 to 0.60, p <0.0001). Of the 126 patients who underwent coronary an giography, severe CAD was identified in only 19 individuals (0.44% of the original cohort, 95% CI 0.26% to 0.62%); coronary artery bypass gr afting was performed in 14 of these patients. The estimated cost of ex ercise treadmill testing to identify 1 case of severe CAD for which su rgical revascularization may provide a survival benefit was $39,623. T he estimated cost per year of life saved was at least $55,274. Thus, a s used in actual practice in 1 center, screening exercise treadmill te sting has a low yield and is costly. This is perhaps in part because o f the low-risk population that was selected and the failure to incorpo rate pretest variables, increasing probability of disease into post-te st clinical decision making. (C) 1998 by Excerpta Medico, Inc.