Aerobic exercise for 90-120 minutes per week modestly reduces depressive symptoms in patients with heart failure, according to a report in the Aug. 1 issue of JAMA.
After 3 months of a supervised exercise program, patients who exercised showed a small but significant reduction in depression scores, compared with patients who received usual care. After an additional 9 months of home exercise, that difference persisted.
The difference was characterized as modest, "and the clinical significance of this small improvement is not known," said James A. Blumenthal, Ph.D., of Duke University, Durham, N.C., and his associates.
However, because the difference was consistent over a full year, it appears to be robust and "is likely to be associated with better social functioning and higher quality of life," they noted.
As many as 40% of patients with heart failure have been reported to have comorbid depression, and as many as 75% of heart failure patients have been reported to have elevated depressive symptoms. But few randomized trials have examined treatment of depression in this patient population.
HF-ACTION (Heart Failure–A Controlled Trial Investigating Outcomes of Exercise Training) found that adding exercise to usual care modestly reduced rates of death from any cause and hospitalization for any cause. Dr. Blumenthal and his colleagues reported on an ancillary study to HF-ACTION in which they further assessed the effects of exercise on depressive symptoms.
The study subjects were 2,322 patients whose HF failed to improve after at least 6 weeks of optimal therapy at 82 medical centers in the United States, Canada, and France. All the subjects had undergone exercise stress testing and had completed the Beck Depression Inventory II at baseline in 2003-2007. The median age was 59 years (range, 19-91 years).
The BDI-II is a self-reported measure of depressive symptoms with a possible score ranging from 0 (no depressive symptoms) to 63 (maximal depressive symptoms). A score of 14 or higher reflects clinically significant depressive symptoms. A total of 28% of the study subjects scored in this range at baseline.
A total of 1,164 subjects were randomly assigned to usual care (the control group) and 1,158 to usual care plus three supervised sessions per week on a treadmill or stationary cycle for 3 months. The exercise group was then given the exercise equipment of their choice to take home and was encouraged to increase to 90 min/week of exercise until they reached 1 year from baseline.
At 3 months, the mean BDI-II score was 8.95 for the exercise group and 9.70 for the control group. At 1 year, the mean scores were 8.86 and 9.54, respectively. Both of these differences are statistically significant, although small, the investigators said (JAMA 2012;308:465-74).
The results were more robust for the subgroup of 653 patients who scored 14 or higher on the BDI-II at baseline. At 3 months, the mean score in the exercise group was 16.66, compared with a mean score of 17.98 in the control group. At 1 year, the mean scores were 15.85 and 17.34, respectively.
In addition, the amount of exercise was inversely associated with the reduction in depressive symptoms. "Compared with a participant reporting no exercise, a participant reporting 90 minutes of exercise per week could be expected to have a 1.55-point lower BDI-II score at 3 months and a 1.67-point lower BDI-II score at 12 months," Dr. Blumenthal and his associates said.
Such a difference "is comparable with placebo-control trials involving patients with major depressive disorder," they added.
"We also observed that elevated depressive symptoms were associated with more than a 20% increase in risk for all-cause mortality and hospitalizations and that the increased risk was independent of antidepressant use and established risk factors in patients with heart failure, including age and disease severity.
"These data add to the evidence suggesting that elevated depressive symptoms, without necessarily meeting diagnostic criteria for major depressive disorder, are associated with increased risk for adverse clinical events," the researchers said.
The study findings also support the recent recommendation by the American Heart Association that all patients with cardiac disease be routinely assessed for depression, they added.
The study results also demonstrated that HF patients whose depression worsened over time were at particularly increased risk for hospitalization and death. This highlights the need to not only reduce depressive symptoms but also to prevent the worsening of existing depressive symptoms, Dr. Blumenthal and his colleagues said.