Gender differences in the prognostic value of exercise treadmill test characteristics.

BACKGROUND: Although exercise treadmill testing (ETT) is less sensitive and specific for diagnosis of coronary disease in women, little is known about gender differences in the prognostic importance of ETT variables.
METHODS: We studied 9,569 consecutive patients (46.8% women) referred for ETT between July 2001 and June 2004 in a community-based system. We assessed the association between ETT variables (exercise capacity, symptoms, ST-segment deviations, heart rate recovery, and chronotropic response) and time to all-cause death and myocardial infarction (MI), adjusting for patient and stress test characteristics. Models were stratified by gender to determine the relationship between ETT variables and outcomes.
RESULTS: In the entire population, exercise capacity and heart rate recovery were significantly associated with all-cause death, whereas exercise capacity, chest pain, and ST-segment deviations were significantly associated with subsequent MI. The relationship between ETT variables and outcomes were similar between men and women, except for abnormal exercise capacity, which had a significantly stronger association with death in men (men: hazard ratio [HR] 2.89 and 95% CI 1.89-4.44, women: HR 0.99 and 95% CI 0.52-1.93, and interaction P = .01), and chronotropic incompetence, which had a significantly stronger relationship with MI in women (men: HR 1.29 and 95% CI 0.74-2.20, women: HR 2.79 and 95% CI 0.94-8.27, and interaction P = .04).
CONCLUSIONS: Although many traditional ETT variables had similar prognostic value in both men and women, exercise capacity was more prognostically important in men, and chronotropic incompetence was more important in women. Future studies should confirm these findings in additional populations.