GENDER AND REFERRAL FOR CORONARY ANGIOGRAPHY AFTER TREADMILL THALLIUMTESTING

Considerable controversy exists regarding whether women are less likel y than men to be referred to coronary angiography after an abnormal no ninvasive test. This prospective cohort study analyzed consecutive sub jects (2,351 men and 1,318 women) with no prior history of invasive ca rdiac procedures who were referred for treadmill thallium testing at t he Cleveland Clinic Foundation. The primary end point was performance of coronary angiography within 90 days of treadmill thallium testing. A secondary end point was all-cause mortality during 1.8 years of foll ow-up. Women were less likely than men to undergo coronary angiography (6% vs 14%, odds ratio [OR] 0.42, 95% confidence interval [CI] 0.33 t o 0.54, p <0.001), but were also less likely to have an abnormal thall ium scan (8% vs 29%, p <0.001). In logistic regression analyses with a djustment for thallium result and age, women were as likely as men to be referred for coronary angiography (adjusted OR 1.00, 95% CI 0.75 to 1.34, p >0.9). Women were less likely to have severe coronary disease on angiography (15% vs 30%, p = 0.006). During 1.8 years of follow-up there were 26 deaths (2%) among women and 84 deaths (4%) among men. A fter adjusting for age, thallium abnormalities, and clinical character istics in Cox regression analyses, women had a lower mortality rate th an men (relative risk 0.58, 95% CI 0.36 to 0.94, p = 0.03). Thus, gend er-related differences in referral for coronary angiography after trea dmill thallium testing can be explained by a higher rate of abnormal t ests in men. No evidence of a post-test gender bias was detected, but a pretest bias affecting referral to nuclear testing cannot be exclude d. Furthermore, women have a lower prevalence of severe coronary disea se and a lower adjusted mortality rate.