Abstract 17: Exercise Capacity and Primary Prevention of Major Adverse Cardiac Events in Veterans: The ETHOS Study
Introduction: Increased exercise capacity is associated with better health outcomes. However, less is known about the impact of increased fitness on the primary prevention of major adverse cardiovascular events (MACE) defined as fatal or non-fatal myocardial infarction, cardiac bypass surgery, heart failure or stroke, has not been determined.
Hypothesis: We assessed the hypothesis that increased exercise capacity decreases the risk of primary MACE.
Methods: We identified 21,062 veterans (mean age:58.4±11.4) who completed an exercise stress test to either assess fitness status or suspected ischemia at two VA Medical Centers (Washington DC and Palo Alto, Ca). None had documented cardiovascular disease or any evidence of ischemia during the test.
We established five fitness categories based on age-stratified quintiles of peak metabolic equivalents (MET) achieved: Least-Fit (4.2±1.2 METs; n=4,035); Low-Fit (6.0±1.2; n=4,483); Moderate-Fit (7.9±1.0 METs; n=3,898); Fit (8.6±1.4 METs; n=5,115); and High-Fit (11.9±2.3 METs; n=3,531). Multivariable Cox models were used to estimate hazard ratios (HR) and 95% confidence intervals [CI] for incidence of MACE across fitness categories. The models were adjusted for age, BMI, race, gender, cardiac risk factors, sleep apnea, alcohol dependence and medications. The Least-fit category was the referent.
Results: During follow-up (median=11.3 yrs), 2,911 developed MACE. For every 1-MET increase in exercise capacity, the risk for MACE was 15% lower (HR=0.85, 95% CI: 0.84-0.87). When considering fitness categories, MACE risk was lower by: 28% in Low-Fit (HR=0.72; CI: 0.65-0.79); 36% in Moderate-Fit (HR=0.64; 95% CI, 0.57-0.71); 55% in Fit (HR, 0.45; 95% CI, 0.41-0.51); and 66% in High-Fit (HR, 0.34; 95% CI, 0.29-0.39) individuals. Similar trends were noted in each of the MACE components.
Conclusions: Increased exercise capacity protects against primary MACE. The association is independent and graded.
Author Disclosures: P. Kokkinos: None. C. Faselis: None. J. Myers: None. P. Narayan: None.
- © 2016 by American Heart Association, Inc.