Compared with those who did not have 30-day unexpected rehospitalization (group 1), patients in the rehospitalization group (group 2) were older [50.2 ± 16.8 years verse (vs.)46.6 ± 15.2 years, P = 0.013)], had longer length of index hospital stay (26.3 ± 12.0 days vs. 23.5 ± 9.9 days, P = 0.006), lower level of albumin (33.8 ± 5.7 g/L vs. 34.8 ± 5.1 g/L, P = 0.016), higher proportion of hyponatremia [12.9% vs. 6.3%, P = 0.003]. Here, ALB is linked to Hyponatremia.