Lymphoma histology as independent predictor of ICU mortality after adjustment for illness severity: A retrospective cohort study of 1,268 patients.

Abstract

e19106 Background: Lymphomas comprise biologically heterogeneous malignancies ranging from aggressive to indolent subtypes. Whether histologic classification independently predicts intensive care unit (ICU) mortality after accounting for severity of critical illness remains unknown. Methods: We conducted a retrospective cohort study using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database (2008-2022). Adult lymphoma patients requiring ICU admission were classified into histology groups: aggressive non-Hodgkin lymphoma (NHL), indolent NHL, Hodgkin lymphoma, and plasma cell neoplasms. The primary outcome was hospital mortality. Multivariable logistic regression assessed whether histology independently predicted mortality after adjusting for demographics, illness severity, and admission characteristics. Results: Among 1,268 lymphoma patients requiring ICU admission, overall hospital mortality was 19.3%. Unadjusted mortality rates did not differ across histology groups (15.8-20.8%, p=0.79). After multivariable adjustment, histology did not independently predict mortality: Hodgkin lymphoma (adjusted OR 0.86, 95% CI 0.44-1.68, p=0.66), indolent NHL (OR 0.77, 95% CI 0.37-1.59, p=0.48), plasma cell neoplasms (OR 0.99, 95% CI 0.63-1.55, p=0.97), and other lymphomas (OR 1.04, 95% CI 0.69-1.56, p=0.86) versus aggressive NHL. Independent mortality predictors were ICU length of stay (OR 1.53, p<0.001) and emergency admission (OR 3.18, p=0.001). Conclusions: Lymphoma histology does not independently predict ICU mortality after adjustment for critical illness severity. ICU triage decisions and prognostic discussions should focus on acute illness reversibility rather than lymphoma subtype, supporting evidence-based admission policies and equitable resource allocation.