ALB and Hyponatremia: Multivariate logistic regression analysis showed that length of index hospital stay [Odds ratio (OR) = 1.02, 95% confidence interval (CI) 1.00–1.03, P = 0.036] and hyponatremia (OR = 1.85, 95% CI 1.06–3.24, P = 0.031) were positively independently associated with 30-day unexpected rehospitalization after adjusting for age, gender, diabetes mellitus, CVD history and albumin (Table 2).