Protein-Energy Malnutrition, Rescue-Sensitive Mortality and Utilization in Hospitalized Diffuse Large B-Cell Lymphoma: National Inpatient Sample, 2016-2020

Background: Protein Energy Malnutrition is an important marker for impaired physiological reserve in patients with cancer; however, its implication in patients with Diffuse B Cell Lymphoma (DLBCL) is not fully characterized at a national level. Previous studies on DLBCL have described inpatient mortality and utilization trends, focusing on chemotherapy-focused cohorts, but have not specifically centered on malnutrition as the primary exposure within a broader diagnosis-defined inpatient population. We evaluated whether PEM is independently associated with in-hospital mortality, failure-to-rescue, discharge disposition, and hospital utilization among U.S. hospitalizations involving DLBCL.

Methods: We performed a retrospective encounter-level study using NIS data from 2016 through 2020. Adult DLBCL hospitalizations and PEM hospitalizations were identified using ICD-10-CM code 83.3. The primary outcome was in-hospital mortality. Secondary outcomes were failure to rescue, defined as in-hospital death among admissions with severe complications, non-home discharge among survivors, length of stay (LOS), and total hospital charges. 

Results: Among 72,832 adults with DLBCL admissions, PEM prevalence was 15.5% and increased from 12.2% in 2016 to 17.8% in 2020. Severe complications occurred in 39.09% of admissions (95% CI 38.52%- 39.66%), with descriptive mortality of 10.79% (95% CI 10.41%-11.17%) in the severe-complication subgroup. After adjustment, PEM was associated with higher in-hospital mortality (odds ratio [OR] 3.09, 95% CI 2.85-3.36; adjusted risk 10.03% vs 3.51%; risk difference +6.52 percentage points), higher adjusted failure-to-rescue mortality (OR 1.91, 95% CI 1.75-2.08; 19.91% vs 11.56%; +8.35 percentage points), and higher non-home discharge among survivors (OR 3.09, 95% CI 2.94-3.26; 54.58% vs 30.83%; +23.74 percentage points). PEM was also associated with longer length of stay (+5.69 days, 95% CI +5.36 to +6.02) and higher total charges (+68.1%, 95% CI 63.5%-72.7%). Severe-PEM sensitivity analysis remained concordant (E43 only: OR 3.22, 95% CI 2.92-3.56), and interaction tests by year and income quartile were not statistically significant.

Conclusions: In a nationally representative inpatient DLBCL cohort, PEM identifies a high-risk and high-cost phenotype associated with substantially worse mortality, poorer rescue after severe complications, greater non-home discharge burden, longer hospitalization, and higher charges. These findings support PEM as more than a passive comorbidity label and suggest that systematic nutrition-risk screening and early inpatient nutrition-focused intervention pathways may represent clinically meaningful targets for improving outcomes and reducing utilization burden in hospitalized patients with DLBCL.