Abstract 14643: Does Cardiorespiratory Fitness Have the Same Prognostic Value in Men and Women? Data From the FIT Project
Background: Fitness is an important risk factor for mortality from any cause. While it is known that fitness differs by sex, the impact of sex on the association between fitness and mortality is unknown.
METHODS: We included 55,124 consecutive patients without known coronary disease or heart failure who completed a routine symptom limited treadmill exercise test in a single clinical non-invasive laboratory between 1991 and 2009. Patients were followed for all-cause mortality as determine by a search of social security death index in 4/2013. Multivariable Cox regression was used including interaction terms to determine the association between gender, fitness, and all-cause mortality.
RESULTS: The mean age was 53 years. The population was 51% male and 29% black. Female patients (n=25,727) were older (54 vs. 52 yr, p<0.001), but had higher prevalence of hypertension (63% vs. 58%, p<0.001)) and diabetes (18% vs. 17%, p=0.006). Men had higher cardiorespiratory fitness (as measured by estimated metabolic equivalents, METs) compared to women (median METs 10.2 vs. 8.3, p<0.001, respectively). During a median follow-up of 10 years (range: 3 days to 22.5 years), there were 3,375 deaths among men and 2,486 deaths among women. The unadjusted 10 yr cumulative incidence was 0.41 and 0.21 in men and women achieving 12 METs or more. A graded increase in mortality was associated with a decrease in exercise capacity for both men and women patients (p<0.001). In multivariable Cox regression, METs demonstrated a strong inverse association with all-cause mortality: Men = adjusted Hazard ratio for 12 METs = 0.21 (95% CI: 0.18, 0.24); Women = adjusted hazard ratio = 0.24 (95% CI: 0.17, 0.32). Further, this inverse relationship was stronger in men versus women (figure, P-interaction < 0.001)
CONCLUSIONS: Among patients free of known cardiovascular disease, our data suggest that gender is an independent consideration when interpreting the prognostic importance of cardiorespiratory fitness.
- © 2013 by American Heart Association, Inc.