AVP and clostridium difficile infection: Although preoperative copeptin levels of 12 patients in the permanent CDI group (57.1%) was < 2.6 pmol/L [18 in the non-CDI group (38.3%) and 5 in the transient CDI group (29.4%)], they showed no clinical signs of CDI and preoperative copeptin levels were comparable among three groups (Fig. 1a).