Malnutrition severity and nutrition care in hospitalized adults: A descriptive cohort study

Malnutrition is prevalent in acute hospital populations. Morrison Healthcare launched a data system enabling hospitals to track and report malnutrition, including dietitian diagnosis, assigned ICD-10 codes, nutrition interventions, and length of stay. This study aimed to describe characteristics of adults with malnutrition and examine associations between nutrition care and hospital length of stay.

This descriptive cohort study analyzed de-identified data from hospitalized adults with malnutrition identified by a dietitian and/or ICD-10 coded at discharge between December 2019 and January 2025. Categorical variables are reported as frequencies (%) and continuous variables as means ± SD. Chi-square tests assessed associations between malnutrition diagnosis and patient characteristics. Regression was used to examine associations between patient characteristics, nutrition interventions, and hospital length of stay.

Among patients with malnutrition identified by either source, dietitians diagnosed severe malnutrition in 102,484 (57.2%) and mild/moderate malnutrition in 50,780 (28.4%). Malnutrition was identified by dietitians in a higher proportion of patients than was documented using ICD-10 codes (85.6% vs. 76.1%, P < 0.001). Mean length of stay was 9.6 (11.7) days and was significantly different between malnutrition diagnosis groups. Early assessment by a dietitian within 24 h was associated with ~31% shorter length of stay. Length of stay was shorter in patients with malnutrition who received oral or enteral nutrition support.

Differences between dietitian-identified malnutrition and ICD-10 coded malnutrition highlight variability in documentation practices. Earlier dietitian assessment and selected nutrition interventions were associated with differences in hospital length of stay. Further research is needed to evaluate causal relationships and long-term impacts of nutrition care.