FNDC5 and sarcopenia: Nonparametric tests revealed significant differences between the no sarcopenia and sarcopenia groups for irisin levels in the Child–Pugh A (Z = 2.401, p = 0.016), Child–Pugh B (Z = 6.590, p < 0.001) and Child–Pugh C (Z = 5.249, p < 0.001) classes (Fig. 1; Table 3).