Impact of protein-energy malnutrition on in-hospital outcomes in patients undergoing bone marrow transplantation: Insights from a national inpatient sample

Abstract Background: Protein-energy malnutrition (PEM) is a known contributor to adverse clinical outcomes, particularly in immunocompromised populations. Its role in patients undergoing bone marrow transplantation (BMT) remains understudied. Objective: To evaluate the prevalence of PEM among hospitalized BMT patients and assess its association with in-hospital mortality, length of stay (LOS), and total hospitalization charges using the National Inpatient Sample (NIS). Methods: We conducted a retrospective cross-sectional analysis using the 2021 NIS database. Adult patients undergoing BMT were identified using ICD-10 procedure codes. PEM was identified using ICD-10 diagnostic codes across diagnosis fields. Survey-weighted logistic and linear regressions were performed to assess associations with in-hospital mortality, LOS, and hospitalization charges. Multivariable models adjusted for age, sex, race, Charlson comorbidity index, income quartile, hospital region, bed size, and teaching status. Results: Among 4,033 hospitalized patients who underwent bone marrow transplantation (BMT), 13.9% were diagnosed with protein-energy malnutrition (PEM). The presence of PEM was significantly associated with worse clinical outcomes. In-hospital mortality was higher in the PEM group compared to those without PEM (9.3% vs. 3.9%, p<0.001), with a crude odds ratio (OR) of 2.52 (95% CI: 1.81–3.49). This association remained significant after adjusting for demographic and hospital-level covariates, with an adjusted OR of 2.42 (95% CI: 1.73–3.37, p<0.001). Patients with PEM also had significantly longer hospital stays, averaging 12.9 days compared to 6.8 days in non-PEM patients. Multivariable linear regression confirmed that PEM was independently associated with an increase in length of stay by 6.3 days (95% CI: 4.8–7.8, p<0.001). Furthermore, total hospitalization charges were markedly higher in the PEM cohort, with a mean of $210,153 compared to $113,456 in those without PEM. Adjusted analysis demonstrated an independent association between PEM and increased hospital charges by approximately $99,791 (95% CI: $65,367–$134,215, p<0.001). Conclusion: Protein-energy malnutrition is prevalent among BMT recipients and is independently associated with increased in-hospital mortality, prolonged hospitalization, and higher healthcare costs. These findings highlight the need for early nutritional screening and targeted interventions in this high-risk population.