Vitamin D Status and Exercise Capacity in Older Patients with Heart Failure with Preserved Ejection Fraction

Abstract

Background: Older patients with heart failure with preserved ejection fraction have severe exercise intolerance. Vitamin D may play a role in cardiovascular and skeletal muscle function, and may therefore be implicated in exercise intolerance in heart failure with preserved ejection fraction. However, there are few data on vitamin D status and its relationship to exercise capacity in heart failure with preserved ejection fraction patients.

Methods: Plasma 25-hydroxyvitamin D (25[OH]D) and exercise capacity (peak oxygen consumption, [VO₂], 6-minute walk distance) were measured in 112 older heart failure with preserved ejection fraction patients (mean ± SD age = 70 ± 8 years) and 37 healthy age-matched controls. General linear models were used to compare 25(OH)D between heart failure with preserved ejection fraction patients and healthy controls, and to determine the cross-sectional association between 25(OH)D and exercise capacity. The association between 25(OH)D and left ventricular function was evaluated secondarily in heart failure with preserved ejection fraction patients.

Results: 25(OH)D concentrations were significantly lower in heart failure with preserved ejection fraction vs healthy controls (11.4 ± 0.6 ng/mL vs 19.1 ± 2.1 ng/mL; P = .001, adjusted for age, race, sex, body mass index, season). More than 90% of heart failure with preserved ejection fraction patients had 25(OH)D insufficiency (<20 ng/mL) and 30% had frank 25(OH)D deficiency (<10 ng/mL). In heart failure with preserved ejection fraction patients, but not healthy controls, 25(OH)D was significantly correlated with peak VO₂ (r = 0.26; P = 0.007) and 6-minute walk distance (r = 0.34; P < .001).

Conclusions: More than 90% of heart failure with preserved ejection fraction patients had 25(OH)D insufficiency, and 30% were frankly deficient. Lower 25(OH)D was associated with lower peak VO₂ and 6-minute walk distance in heart failure with preserved ejection fraction, suggesting that 25(OH)D insufficiency could contribute to exercise intolerance in this patient population. These findings provide the data and rationale for a future randomized trial designed to test the potential for vitamin D supplementation to improve exercise intolerance in heart failure with preserved ejection fraction.

Keywords: Aging; Exercise capacity; Heart failure with preserved ejection fraction; Skeletal muscle; Vitamin D.