Abstract PS5-11-27: Impact of Protein Energy Malnutrition on Clinical Outcomes in Hospitalized Breast Cancer Patients

Abstract Background Protein Energy Malnutrition (PEM) is associated with adverse outcomes in hospitalized patients, yet its impact among those with breast cancer remains poorly characterized. This study evaluates the burden of PEM and its effect on inpatient mortality, length of stay, and hospitalization charges in breast cancer hospitalizations. Methods We analyzed the 2021 National Inpatient Sample to identify breast cancer hospitalizations and cases of PEM using appropriate ICD10 codes. Survey-weighted logistic and linear regressions assessed the association between PEM and clinical outcomes. Models adjusted for age, sex, race, Charlson Comorbidity Index, ZIP code income quartile, hospital location (urban or rural), teaching status, region, and bed size. Results A total of 491634 hospitalizations were identified as breast cancer related. Among these, 98327 patients (20 percent) had a diagnosis of Protein Energy Malnutrition. PEM prevalence was highest in the South (24 percent), followed by the Midwest (18 percent), Northeast (17 percent), and West (15 percent). The cohort had a mean age of 65.2 years, and 63.4 percent were female. Racial distribution included 67.1 percent White, 16.9 percent Black, 9.8 percent Hispanic, and 6.2 percent from other racial groups. More than 60 percent of patients had a Charlson Comorbidity Index score of three or greater. The majority of hospitalizations occurred in teaching hospitals (75.4 percent) and urban facilities (92.2 percent). In adjusted analyses, PEM was independently associated with significantly worse clinical and economic outcomes. Patients with PEM had more than twice the odds of in-hospital mortality compared to those without PEM (adjusted odds ratio 2.41, 95 percent confidence interval 2.25 to 2.59, p less than 0.001). Additionally, PEM was associated with an average increase of 5.3 days in length of stay (beta equals 5.33, 95 percent confidence interval 5.09 to 5.58, p less than 0.001) and 65294 dollars higher total hospitalization costs (beta equals 65294, 95 percent confidence interval 57863 to 72726, p less than 0.001). Conclusion In this national cohort of hospitalized breast cancer patients, one in five had documented Protein Energy Malnutrition. The presence of PEM was strongly associated with increased in-hospital mortality, prolonged hospital stay, and substantially higher hospitalization costs. The disproportionately high burden in the Southern United States underscores potential regional disparities in nutritional screening, access to care, and social determinants of health. These findings highlight the critical importance of early nutritional screening and intervention to improve outcomes in this vulnerable population. Citation Format: K. Babu, S. Rajarajan, M. Jin, R. Dileo, G. Gorecki, S. Arivazhagan, C. J. Hilton. Impact of Protein Energy Malnutrition on Clinical Outcomes in Hospitalized Breast Cancer Patients [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS5-11-27.