Low physical activity levels tied to adverse outcomes in HFpEF
Both poor and intermediate physical activity (PA) present a twofold increased risk of heart failure (HF) hospitalization and mortality to patients with HF with preserved ejection fraction (HFpEF), according to a posthoc analysis of the TOPCAT* trial.
In a cohort of 1,751 HFpEF patients (mean age at baseline 68.6 years) enrolled in the Americas region of the trial, the primary study outcome of composite of death from a cardiovascular cause (n=222), aborted cardiac arrest (n=6) or HF hospitalization (n=397) occurred in 519 patients during a median follow-up of 2.4 years. [Circulation 2017;136:982-992]
Compared with HFpEF patients with ideal PA, those with poor and intermediate PA had greater risk of the primary composite outcome. The corresponding hazard ratios (HRs) were 2.05 (95 percent CI, 1.28 to 3.28) and 1.95 (1.15 to 3.33).
When individual components of the outcome were evaluated, poor PA was associated with an increase of 1.93 fold (1.16 to 3.22) in HF hospitalization, 4.36 fold (1.37 to 13.83) in cardiovascular mortality and 2.95 fold (1.44 to 6.02) in all-cause mortality. The respective values observed with intermediate PA were 1.84 (1.02 to 3.31), 4.05 (1.17 to 14.04) and 2.05 (0.90 to 4.67).
“These associations were strongest in the first 2 years following baseline activity assessment,” suggesting that the impact of PA changes over time, the authors said.
In the cohort, only 11 percent met the American Heart Association (AHA) criteria for ideal activity, with 14 percent having intermediate PA and the majority (75 percent) having poor PA.
Ideal PA was defined as ≥150 min/wk of moderate activity, ≥75 min/wk of vigorous activity or ≥150 min/wk of moderate + vigorous activity; intermediate PA as 1 to 149 min/wk of moderate activity, 1 to 74 min/wk of vigorous activity or 1 to 149 min/wk of moderate + vigorous activity; and poor PA as 0 min/wk of moderate + vigorous activity.
The authors pointed out that the underlying mechanism of association between baseline PA and lower risk of adverse outcomes may be related to better indices of diastolic function in more active participants and to peripheral mechanisms such as improvements in skeletal muscle function.
However, it is important to note several caveats when interpreting the findings, the authors said. These include the self-report nature of PA, which is subject to recall bias, and the dissipation of the relationship between baseline PA and outcomes in the first 2 years, limiting generalizability of outcomes beyond the said period.
Future prospective randomized studies are warranted to evaluate the role of physical activity, including the appropriate “dose” and type of exercise, on outcomes in patients with HFpEF.
In a linked commentary, Drs Ambarish Pandey and Jarett Berry from the University of Texas Southwestern Medical Center noted that the present study represents an important step in elucidating the prognostic role of physical activity levels among patients with HFpEF. [Circulation 2017;136:993-995]
“[The findings] suggest that some exercise may not be an improvement over no exercise among HFpEF patients and that a higher dose of exercise may be required to achieve clinical benefits,” they said, highlighting their potential implications for future research and clinical practice alike.
Pandey and Berry called for additional studies to test whether modifying physical activity levels might modify risk in HFpEF patients.
“In the interim, in the absence of documented treatments for these patients, [the present] study reminds us that we may already have one of the safest and cost-effective therapies available for HFpEF patients,” they said.
*Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist