Risk factors for malnutrition and its impact on prognosis in patients with severe pneumonia

Malnutrition is common in acute and critical illness, but its clinical correlates and prognostic relevance in severe pneumonia remain incompletely characterized. This study investigated factors associated with malnutrition at admission and its association with short-term outcomes in patients with severe pneumonia.

In this retrospective cohort study, adults with severe pneumonia treated between January 2021 and December 2024 were consecutively included. Malnutrition at admission was defined using the Global Leadership Initiative on Malnutrition (GLIM) framework. Univariable and multivariable logistic regression analyses were used to identify factors associated with malnutrition. Logistic regression and Cox proportional hazards models were used to examine the association between malnutrition and clinical outcomes. Pre-specified subgroup and sensitivity analyses were performed.

Among 211 eligible patients, 59 (28.0%) were classified as having malnutrition at admission. Malnourished patients had a less favorable admission profile, including greater comorbidity burden, more severe inflammatory and respiratory abnormalities, and higher illness severity. In multivariable analysis, lower body mass index, lower serum albumin, higher procalcitonin, higher Acute Physiology and Chronic Health Evaluation II (APACHE II) score, heart failure, and chronic kidney disease were independently associated with malnutrition. Malnutrition was also associated with less favorable short-term outcomes, including higher in-hospital and 28-day mortality, greater intensive care unit utilization, longer hospitalization, and higher hospital costs. After adjustment for major clinical confounders, malnutrition remained significantly associated with mortality-related endpoints, intensive care unit (ICU) admission, invasive mechanical ventilation, and a lower rate of discharge alive. These findings were directionally consistent in subgroup and sensitivity analyses.

GLIM-defined malnutrition was frequent in severe pneumonia and was associated with an adverse clinical profile and less favorable short-term outcomes. These findings suggest that malnutrition may represent a clinically relevant marker of vulnerability in this population.