Enhanced risk assessment in asymptomatic individuals with exercise testing and Framingham risk scores

Background - National Cholesterol Education Program Adult Treatment Panel III ( ATP III) guidelines recommend the use of Framingham risk scores ( FRS) for cardiovascular assessment of asymptomatic individuals. We hypothesized that risk prediction could be improved with 2 non-ECG exercise test measures, exercise capacity ( metabolic equivalents, or METs) and heart rate recovery (HRR). Methods and Results - An asymptomatic cohort with baseline treadmill tests (n = 6126; 46% women, FRS < 20%) was followed up prospectively for 20 years. Individuals with low ( median or less) HRR or METs experienced 91% of all cardiovascular disease (CVD) deaths (225/246). After FRS adjustment, low HRR and METs individually were highly significant predictors of CVD death, but low HRR and METs together were associated with substantially higher risk ( adjusted hazard ratio compared with high HRR/high METs for women 8.51, 95% CI 3.65 to 19.84; for men, 3.53, 95% CI 2.03 to 6.15; P < 0.001 for both). At 10-year follow-up, FRS-adjusted CVD death risk associated with low HRR/ low METs was less than at 20 years but remained significant (women 3.83, 95% CI 1.09 to 13.47, and men 2.70, 95% CI 1.11 to 6.55). The application of HRR/ METs information to FRS assessment identified those at high risk ( > 0.5% annual CVD mortality) in half of women with FRS 6% to 9% and 10% to 19% and just under half of men with FRS 10% to 19%. Low HRR/ low METs was also associated with an increased relative risk of CVD death in individuals with low- risk FRS ( FRS <6% in women and <10% in men), but absolute CVD mortality rates were low in this subgroup. Conclusions - Exercise testing may be a useful adjunct for clinical risk assessment in asymptomatic women with FRS 6% to 19% and men with FRS 10% to 19%.