Aerobic Exercise May Benefit Patients With Heart
Failure, Finds JAMA Studies
Modest reduction in risk of death and
hospitalization, some improvement in quality of life, according to two
studies
April 7, 2009 - Aerobic exercise training appears
safe for patients with heart failure and was associated with a modest
reduction in the risk of death and hospitalization, with some
improvement in quality of life, according to two articles in the April 8
issue of the Journal of the American Medical Association (JAMA).
Heart failure is a major and increasingly common
cardiovascular syndrome, and is the end result of many cardiovascular
disorders. In the United States, an estimated 5 million patients have
heart failure and an additional 500,000 new cases are diagnosed
annually.
Many of these patients treated with drug and device
therapies often still have breathing difficulties and fatigue,
diminished exercise tolerance, reduced quality of life, recurrent
hospitalizations and premature death, according to background
information in the article.
Guidelines recommend that exercise training be
considered for medically stable outpatients with heart failure, but
there have remained concerns regarding safety and uncertainty about
clinical outcomes.
Christopher M. O'Connor, M.D., of Duke University
School of Medicine, Durham, N.C., and colleagues working with Heart
Failure: A Controlled Trial Investigating Outcomes of Exercise Training
(HF-ACTION), examined whether aerobic-type exercise training reduces
all-cause death or all-cause hospitalization in patients with medically
stable chronic heart failure due to systolic dysfunction (impaired
contraction of the heart).
There were 2,331 patients in the study with a
median age of 59. They were randomly assigned to either usual care plus
aerobic exercise or usual care alone.
The aerobic exercise training consisted of 36
sessions of supervised aerobic exercise - walking, treadmill or
stationary cycling - three times per week. This was followed by
prescribed home-based training at the same intensity 5 times per week.
Usual care alone included optimal medical therapy
and a recommendation for regular physical activity.
Exercise adherence decreased from a median of 95
minutes per week during months 4 through 6 of follow-up to 74 minutes
per week during months 10 through 12. Median follow-up was 30 months.
During follow-up, 759 patients in the exercise
training group (65%) and 796 patients in the usual care group (68%) died
or were hospitalized.
In the primary analysis, exercise training resulted
in an insignificant reduction in the primary end point of all-cause
death or hospitalization.
There was no significant difference in the number
of deaths in the exercise training group (16%) vs. in the usual care
group (17%).
Exercise training had an insignificant reduction in
the combined end point of cardiovascular death or cardiovascular
hospitalization in the main analysis in the exercise training group
(55%) vs. in the usual care group (58%).
There was an insignificant reduction in
cardiovascular death or heart failure hospitalization in the exercise
training group vs. in the usual care group.
After adjusting for highly prognostic predictors of
the primary end point, exercise training was found to significantly
reduce the incidence of all-cause death or all-cause hospitalization by
11% and cardiovascular death or heart failure hospitalization by 15%.
Other adverse events were similar between the
groups.
"The change from an nonsignificant to a significant
result after adjustment for strongly predictive factors is unusual in
large clinical trials, but can occur when the treatment differences are
close to significance. The overall interpretation of the results, then,
is that this structured exercise training intervention had at best a
modest effect on clinical end points in a large cohort of patients," the
authors write.
"Based on the safety of exercise training and the
modest reductions in clinical events..., the HF-ACTION results support a
prescribed exercise training program for patients with reduced left
ventricular function and heart failure symptoms in addition to
evidence-based therapy," the researchers conclude.
Exercise Training Improves Health Status of
Heart Failure Patients
Patients with heart failure who participated in
aerobic exercise training had modest improvements in self-reported
health status compared to those patients who did not have exercise
training, according to the second article appearing in JAMA.
Patients with heart failure often experience
diminished health status, including reductions in physical and social
functioning and other dimensions of health-related quality of life.
"Pharmacological and device interventions and
disease management programs for heart failure have provided little or
modest improvements in health-related quality of life. The extent to
which exercise training in addition to optimal evidence-based therapy
improves patients' health status is unknown," the authors write.
Kathryn E. Flynn, Ph.D., of Duke University School
of Medicine, Durham, N.C., and colleagues examined the effects of
exercise training on health status among patients with heart failure who
were participants of HF-ACTION.
Health status was assessed using the Kansas City
Cardiomyopathy Questionnaire (KCCQ), a 23-item self-administered
disease-specific survey. The KCCQ is scored from 0 to 100, with higher
scores representing better health status. HF-ACTION compared scores on
the KCCQ overall summary scale and key subscales (i.e., physical
limitations, symptoms, quality of life and social limitations) between
randomized groups. Median follow-up was 2.5 years.
At 3 months, usual care plus exercise training led
to greater improvement in the KCCQ overall summary score compared with
usual care alone.
Neither group experienced significant changes in
KCCQ scores after 3 months, resulting in a sustained, greater
improvement overall for the exercise group.
At 12 months, 53 percent of patients in the
exercise training group had a clinically noticeable improvement from the
beginning of the trial compared with 33 percent in the usual care group.
Results for the KCCQ subscales were similar to the
results for the overall summary scale. After adjusting for the cause of
heart failure, there was a significant overall treatment effect on
physical limitations, symptoms, quality of life and social limitations.
"The results demonstrate that participation in an
exercise training program provides a modest but statistically
significant improvement in patient-reported health status compared with
usual care. The clinical meaningfulness of the magnitude of average
change requires further study," the authors conclude.
