Abstract MP78: Effect of Beta-Blocker Therapy, Maximal Heart Rate and Exercise Capacity During Stress Testing on Long-Term Survival
Background: Whether beta-blocker therapy (BBT) attenuates the prognostic value of percentage-predicted maximal heart rate (ppMHR) achieved during stress testing remains unclear. The combined effect of ppMHR and exercise capacity on long-term mortality is unknown.
Methods: We analyzed 67,772 adults (54 ± 13 years old, 54% men (36,639 of 67,772), 29% black (19,834 of 67,772)) from The FIT Project, a retrospective cohort study of patients who underwent physician-referred exercise stress testing at a single healthcare system between 1991 and 2009. Patients were categorized by baseline use of BBT. Maximal age-predicted heart rate was defined as 220-age. We derived adjusted mortality rates over the range of ppMHR using margins of response logistic regression models. Our primary model included adjustment for demographic data, resting blood pressures, medical history, pertinent medications, and indication for stress testing. Our secondary model included further adjustment for exercise capacity.
Results: There were 10,594 deaths over 11 ± 5 years of follow-up. Patients on BBT tended to have more comorbidities and other medication use (P<.001). After accounting for differences between BBT groups, BBT was associated with an 8% lower ppMHR (83% in BBT vs. 91% in no BBT) in both men and women. ppMHR was inversely associated with all-cause mortality in both analyses performed (P≤.001), though the association was significantly attenuated by BBT (P=.03) [Panel A]. Exercise capacity further attenuated the prognostic value of ppMHR in all patients, particularly in those on BBT, and reduced the difference in risk between those on BBT and not on BBT (P=.08) [Panel B].
Conclusion: BBT attenuated the association between ppMHR achieved during stress testing and long-term mortality. Exercise capacity further attenuated the prognostic significance of ppMHR, particularly in patients on BBT.
Author Disclosures: R.K. Hung: None. M. Al-Mallah: None. S.P. Whelton: None. R.S. Blumenthal: None. C.A. Brawner: None. S.J. Keteyian: None. M.J. Blaha: None.
- © 2015 by American Heart Association, Inc.