“Dose-dependent” impact of recurrent cardiac events on mortality in patients with heart failure

Background —The mortality impact of recurrent cardiac hospitalizations has not been delineated in community-based heart failure patients. The authors determined if a "dose-dependent" relationship exists between heart failure events and death, accounting for temporal changes in age, comorbidities, and disease severity.

Methods —Among heart failure patients in the Enhanced Feedback For Effective Cardiac Treatment Study with onset between April 1999 and March 2001, the investigators compared long-term survival (until March 2006) in those with recurrent heart failure or cardiovascular events, relative to those free of such events.

Results —In 9,138 patients, 28,442 person-years of follow-up were examined (mean age: 75.3 years, 49.6% male). Recurrent heart failure events occurred 1, 2, 3, and ≥4 times in 2,352 (25.7%), 1,020 (11.2%), 505 (5.5%), and 596 (6.5%) patients, respectively. Cardiovascular readmissions occurred 1, 2, 3, and ≥4 times in 2,522 (27.6%), 1,509 (16.5%), 975 (10.7%), and 1,672 (18.3%) patients, respectively.  Compared with those without recurrent heart failure events, the adjusted relative mortality rates for 1, 2, 3, and ≥4 heart failure events were 2.41 (95% confidence interval [CI], 2.24-2.60), 3.00 (95% CI 2.72-3.32), 4.00 (95% CI, 3.51-4.56), and 5.16 (95% CI, 4.55-5.85), respectively. Compared with those without cardiovascular events, the adjusted relative mortality rates for 1, 2, 3, and ≥4 cardiovascular events were 3.33 (95% CI, 3.05-3.63), 4.61 (95% CI, 4.16-5.10), 6.29 (95% CI, 5.59-7.07), and 8.95 (95% CI, 8.05-9.95), respectively.

Conclusions —The risk of death increases progressively and independently with each heart failure or cardiovascular event.  The number of prior events predicts mortality and should be ascertained in patients with heart failure.