FGF23 and atrial fibrillation: Both BNP {U = 13517, P < 0.001; median [interquartile range (IQR)] 1.650 (0.522–3.917) vs. 2.958 (01.458–4.589)} and FGF-23 [U = 14263, P < 0.001; median (IQR) 3.330 (2.784–3.984) vs. 3.604 (3.067–4.946)] were significantly elevated in patients with AF compared with those in sinus rhythm (Figure 4).