Low-Level Vitamin D Is Associated with Atrial Fibrillation in Patients with Chronic Heart Failure

BACKGROUND: Atrial fibrillation (AF) frequently accompanies heart failure (HF), and causes exacerbation of symptoms and treatment failure in such patients. Vitamin D was recently suggested to be an important mediator of cardiovascular disease, including HF. OBJECTIVES: The aim of this study was to evaluate the relationship between vitamin D deficiency and AF in patients with chronic HF. MATERIAL AND METHODS: The study included 180 chronic HF patients that were divided into 2 groups based on having sinus rhythm [AF (-) group] or chronic AF [AF (+) group]. Vitamin D status was assessed via measurement of the serum 25-hydroxyvitamin D (25[OH]D) concentration. RESULTS: Mean age of the patients was 66 ± 8.7 years and 53.9% were male. There weren't any significant differences in age, gender, body mass index, etiology or chronic HF stage between the 2 groups. The vitamin D level in the AF (+) group was significantly lower than in the AF (-) group (11.05 ng/mL vs. 20 ng/mL, p < 0.001) and the parathyroid hormone level was significantly higher in the AF (+) group (76.7 vs. 55 pq mL, p < 0.001). The left atrium to body surface area ratio (LA/BSA) was significantly higher in the AF (+) group (45.03 mm/m2 vs. 42.05 mm/m2, p < 0.01). Independent predictors (based on multiple regression) of AF were vitamin D level (OR = 0.854, 95% CI: 0.805-0.907, p < 0.001) and LA/BSA ratio (OR = 1.077, 95% CI: 1.003-1.156, p < 0.05). The optimal vitamin D cut-off value for the prediction of AF was 16.50 ng/mL, with a sensitivity of 76.0% and specificity of 65.5% (AUC = 0.75, 95% CI: 0.67-0.82). CONCLUSIONS: A low plasma vitamin D concentration was strongly associated with AF in patients with chronic HF.