Sex differences in evaluation and outcome after stress testing

To examine sex differences in evaluation and outcome after stress testing for coronary artery disease (CAD) in a geographically defined cohort.

Subjects were residents of Olmsted County, Minnesota, who underwent an initial stress test between January 1, 1987, and December 31, 1990. End points included referral for coronary angiography, death, and cardiac events, defined as cardiac death, nonfatal myocardial infarction, or congestive heart failure.

A total of 2276 men and 1270 women under went stress tests. Women were older and had more risk factors and comorbidities (P < .05). Among persons without documented CAD (86% of the cohort), the median probability of CAD was 11% (interquartile range, 5%-25%) for men and 8% (interquartile range, 2%-31%) for women (P < .001). Within 6 months after stress testing, 9% of men and 7% of women underwent coronary angiography. Among persons without documented CAD, there was no sex difference in referral for angiography when the stress test result was negative. When the test result was positive, men were more likely to be referred for angiography (adjusted odds ratio [OR] for male sex, 2.02; 95% confidence interval [CI], 1.21-3.38; P = .008). After adjusting for the predicted probability of CAD, this association was no longer detected (adjusted OR for male sex, 0.67; 95% CI, 0.26-1.73; P = .41). Among persons with documented CAD, no sex difference was noted. After a mean +/- SD follow-up of 7.6 +/- 2.7 years and among persons without documented CAD, male sex was associated with a higher adjusted risk of death (relative risk for male sex, 1.40; 95% CI, 1.05-1.86; P = .02) and cardiac events (relative risk for male sex, 1.67; 95% CI, 1.24-2.26; P < .001). Among persons with documented CAD, no sex difference in outcome was noted.

These population-based data indicate that, when the diagnosis of CAD was not established, there was a greater use of angiography among men with positive stress test results, which could be attributed to the increased probability of CAD in men. In the absence of documented CAD, men fared worse than women, with an increase in the risk of death and cardiac events. Among persons with documented CAD, no sex difference in use of angiography and outcome was noted.