In non-surgical inpatients, the associated factors in the univariate analysis for the length of hospital stay were BMI, serum albumin, targeted therapy, number of combined symptoms at admission, malnutrition risk classified by NRS2002 or MUST, malnutrition identified by GLIM criteria, of which high risk of malnutrition classified by NRS2002 and malnutrition identified by GLIM criteria were found to be associated with the length of hospital stay ≥ 9 d (median hospital stay = 9 d) in the multivariate analysis. This evidence concerns the gene ALB and malnutrition.