Working out on a stationary bicycle or walking on a treadmill just 25 to 30 minutes most days of the week is enough to modestly lower risk of hospitalization or death for patients with heart failure, according to the HF-ACTION trial in the April 8 issue of the Journal of the American Medical Association.
The findings stem from the HF-ACTION trial (A Controlled Trial Investigating Outcomes Exercise Training), which examined the effects of exercise upon patients with heart failure. Christopher O'Connor MD, director of the Duke Heart Center in Durham, N.C., and David Whellan, MD, of Thomas Jefferson University in Philadelphia, led the study.
HF-ACTION enrolled 2,331 patients at 82 study sites throughout the U.S., Canada and France. The researchers randomized the patients into a group that received usual care or to a group that received usual care plus an exercise training program that began under supervision but then transitioned to home-based, self-monitored workouts.
The investigators hypothesized that participation in an exercise program would significantly lower the incidence of death and hospitalization among patients with heart failure. But based on the protocol-specified initial analysis, exercise training produced only a modest, non-significant reduction in the primary endpoint of all-cause hospitalization or all-cause death.
A planned, secondary analysis, however, that took into account the strongest clinical factors predicting hospitalization or death, found exercise to be significantly beneficial.
Researchers said they hope the findings will finally put to rest long-held fears that exercise may be too risky for some patients. "The most important thing we found from this study is that exercise is safe for patients with heart failure, and when adjustments were made for specific baseline characteristics, it significantly improved clinical outcomes," O'Connor said.
Whellan, who is also director of clinical research at the Jefferson Heart Center, said that previous studies sent mixed signals, due, in part, to their small size. "It took a study of this size and duration to determine that exercise is not only safe, but also effective in lowering risk of hospitalization or death for patients with heart failure," he said.
Clinical guidelines indicate that exercise should be considered for stable patients with heart failure, but the lack of definitive data about its long-term benefits has limited Medicare and other insurers from considering an intervention that should be covered.
Participants in HF-ACTION had a significant degree of heart failure, determined by left ventricular ejection rate (LVEF), a measure of how vigorously the heart pumps blood throughout the body. The patients' mean LVEF was 25; a value less than 35 is considered problematic. They were already receiving optimal care--95 percent were taking medications for heart failure, such as ACE-inhibitors or beta-blockers, and 45 percent were using mechanical devices to boost their hearts' ability to pump or to treat arrhythmias. The patients' average age was 59 and almost one-third of them were women.
"These patients were quite sick and were receiving exceptionally good care. That makes the gains they made in the exercise program all the more remarkable," said Whellan.
Patients in the exercise arm started out slowly, with a goal of three, 30-minute workout sessions three times per week. After 18 sessions, they transitioned to workouts at home, with a goal of 40 minutes five days per week on a stationary bicycle or treadmill. In contrast, patients in the usual care arm continued their usual medical therapy and were simply encouraged to be active.
Investigators followed the patients for an average of two and half years, tracking clinical measures of heart failure, quality of life, hospitalization, cardiac events and death rates.
During the study, 68 percent of patients in the usual care arm died or were hospitalized, compared to 65 percent in the exercise arm. There were 198 deaths among patients in the usual care arm, compared to 189 in the exercise arm.
In adjusting for clinical characteristics strongly predictive of outcomes, including history of atrial fibrillation, depression, LVEF status and the patients' initial capacity for exercise, investigators found that exercise led to a significant 11 percent reduction in risk of hospitalization or death for those in the exercise group, according to the authors.
They also found that those