The effect of vitamin D therapy in the improvement of cardiac performance and exercise capacity in patients with heart failure: A double-blind, randomized, placebo-controlled trial

BACKGROUND: Low vitamin D status may contribute to the pathogenesis of heart failure (HF), but therapeutic roles of vitamin D on cardiac performance are not well known. We evaluated vitamin D effects on left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) functional class in patients with HF for the first time. METHODS: This study was a double-blind, randomized, placebo-controlled trial. 110 patients with HF admitted to Shahid Chamran and Khorshid Hospitals, Isfahan, Iran, randomly received 500 mg calcium daily plus either 50000 IU vitamin D3 per week (case group) or placebo (control group) for 6 months. Biochemical variables, LVEF, and NYHA functional class were assessed at baseline and after 6 months. RESULTS: 81 patients completed the study. Vitamin D supplementation increased mean serum 25-hydroxyvitamin D [25(OH)D] concentration in the case group by 33.9 ng/ml (P < 0.001). After 6 months of treatment, both groups showed improvement in LVEF, but the extent of improvement was significant only in the case group (5.48% versus 0.44%, P < 0.001). The NYHA functional class improved in the case group but remained constant in the control group (P < 0.001). CONCLUSION: Vitamin D3 improved LVEF and NYHA functional class in patients with HF and might serve as a new agent for the future treatment of this disease.