Malnutrition as a critical predictor of in-hospital outcomes and resource utilization in heart failure: a 6-year nationwide analysis

Aims: Malnutrition is an under-recognized prognostic risk marker in patients hospitalized with heart failure (HF). We aimed to quantify the burden of documented malnutrition among HF hospitalizations in the United States and evaluate its independent associations with in-hospital mortality, complications, resource utilization, and discharge disposition across a six-year period. Methods: We conducted a retrospective cohort study using the National Inpatient Sample (2017–2022) to identify adult hospitalizations with HF as the principal discharge diagnosis. Malnutrition was identified from secondary diagnosis fields using ICD-10-CM codes E40-E46. Survey-weighted multivariable logistic and linear regression models, adjusted for demographics, comorbidities, and hospital characteristics, were used to evaluate outcomes. Propensity score matching was performed as a sensitivity analysis. Results: Among 6,325,668 HF hospitalizations, 339,685 (5.36%) had documented malnutrition. Malnourished patients were older (mean age 75.2 vs. 71.3 years), had higher comorbidity burden, and higher rates of palliative care involvement (14% vs. 5%) and DNR/DNI orders (27% vs. 14%). After multivariable adjustment, malnutrition was independently associated with increased in-hospital mortality (aOR 2.82, 95% CI 2.73–2.92, p < 0.001), acute kidney injury (aOR 1.45), sepsis (aOR 4.29), and cardiogenic shock (aOR 1.57). Malnutrition was also associated with longer length of stay (+ 3.87 days) and higher total hospital charges (+$59,962). Only 27% of malnourished patients were discharged home versus 45% of non-malnourished patients. Coded malnutrition prevalence rose gradually from 5.09% in 2017 to 5.67% in 2022. Conclusions: Malnutrition affects approximately 1 in 20 HF hospitalizations and is a strong independent risk marker of in-hospital mortality, complications, prolonged hospitalization, higher charges, and non-home discharge. These findings underscore the need for routine nutritional screening and targeted interventions in hospitalized HF patients.