Exercise Blood Pressure and Future Cardiovascular Death in Asymptomatic Individuals

Abstract

Individuals with exaggerated exercise blood pressure (BP) tend to develop future hypertension. It is controversial whether they have higher risk of death from cardiovascular disease (CVD). A total of 6578 asymptomatic Lipid Research Clinics Prevalence Study participants (45% women; mean age, 46 years; 74% with untreated baseline BP <140/90 mm Hg [nonhypertensive]) performing submaximal Bruce treadmill tests were followed for 20 years (385 CVD deaths occurred). Systolic and diastolic BP at rest, Bruce stage 2, and maximal BP during exercise were significantly associated with CVD death. When we compared multivariate hazard ratios and 95% confidence intervals per 10/5-mm Hg BP increments, the association was strongest for rest BP (systolic, 1.21 [1.14 to 1.27]; diastolic, 1.20 [1.14 to 1.26]), then Bruce stage 2 BP (systolic, 1.09 [1.04 to 1.14]; diastolic, 1.09 [1.05 to 1.13]), then maximal exercise BP (systolic, 1.06 [1.01 to 1.10]; diastolic, 1.04 [1.01 to 1.08]). Overall, exercise BP was not significant after adjustment for rest BP. However, hypertension status modified the risk associated with exercise BP (P(interaction)=0.03). Among nonhypertensives, whether they had normal BP (<120/80 mm Hg) or prehypertension, Bruce stage 2 BP >180/90 versus < or =180/90 mm Hg carried increased risk independent of rest BP and risk factors (adjusted hazard ratio for systolic, 1.96 [1.40 to 2.74], P<0.001; diastolic, 1.48 [1.06 to 2.06], P=0.02) and added predictive value (net reclassification improvement, systolic, 12.0% [-0.1% to 24.2%]; diastolic, 9.9% [-0.3% to 20.0%]; relative integrated discrimination improvement, 14.3% and 12.0%, respectively). In asymptomatic individuals, elevated exercise BP carried higher risk of CVD death but became nonsignificant after accounting for rest BP. However, Bruce stage 2 BP >180/90 mm Hg identified nonhypertensive individuals at higher risk of CVD death.