Association of Beta-Blocker Use With Exercise Capacity in Participants With Heart Failure With Preserved Ejection Fraction: A Post Hoc Analysis of the RELAX Trial.

Patients with heart failure with preserved ejection fraction (HFpEF) often receive β-blocker (BB) therapy for management of co-morbidities. However, the association of BB therapy with exercise capacity and health-related quality of life (HRQL) in HFpEF is not well-studied. In this post hoc analysis of the Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in HFpEF (RELAX) trial, which included patients with chronic stable HFpEF with peak exercise capacity assessment at baseline and at 12 and 24 weeks of follow-up, we evaluated the association of BB use with the measures of exercise capacity (peak exercise oxygen uptake), anaerobic threshold, and HRQL (Minnesota living with heart failure questionnaire). Separate linear mixed-effect models were constructed for each outcome with adjustment for treatment arm, demographics, medical history, left ventricular ejection fraction, and duration of heart failure. Of the 216 study participants (median age 69 years, 48.2% women), 76% reported BB use at baseline. Participants with (vs without) BB therapy were older (70 vs 63.5 years, p = 0.001) and had a higher prevalence of ischemic heart disease (44% vs 23%, p = 0.01). In the adjusted linear mixed model, BB use over time was not associated with peak exercise oxygen uptake (β 95% confidence interval [CI] 0.2 (-0.31 to 0.7), p = 0.5) and 6-minute walk distance (β 95% CI 14.69 [-14.25 to 43.63], p = 0.3). However, BB use was associated with a higher anaerobic threshold (β 95% CI 0.32 (0.02 to 0.62), p = 0.036) and better HRQL (lower quality of life as assessed by Minnesota living with heart failure questionnaire score) (β 95% CI -6.68 [-10.96 to -2.4], p = 0.002). Future trials are needed to better evaluate the effects of BB on exercise capacity in patients with chronic stable HFpEF.