Outcomes of Patients with Waldenström Macroglobulinemia in ICU: a Retrospective Multicentric Study.

BACKGROUND:Waldenström macroglobulinemia (WM) is a rare lymphoplasmacytic lymphoma, that can lead to life-threatening complications requiring intensive care unit (ICU) admission. This study aimed to describe the clinical characteristics, WM-specific complications, and outcomes of WM patients admitted to the ICU. METHODS:We conducted a multicenter retrospective study in 6 French ICUs including all patients with WM admitted between 2010 and 2024. The primary outcome was ICU mortality, analyzed using Ridge logistic regression. One-year mortality and associated risk factors were also assessed after ICU admission. RESULTS:A total of 151 patients with WM were admitted to the ICU over the 14-year period. ICU mortality was 20% (n = 30), with infections being the leading cause of death. The main reason for admission was acute respiratory failure, and nearly half of the patients presented with sepsis at admission. The most WM-specific complications included hyperviscosity syndrome (n = 29, 19%) and other IgM-related vascular complications (n = 27, 18%). In Ridge logistic regression, a higher SOFA score (β = 0.099) and autoimmune haemolytic anemia (β = 0.058) were most strongly associated with ICU mortality, whereas, hyperviscosity syndrome (β = -0.045) showed the strongest negative association. The one-year mortality rate was 40% (n = 58) and remission at one year was achieved in 47% (n = 56) of treated patients. CONCLUSION:This is the first large retrospective cohort of critically ill patients with WM. SOFA score and autoimmune cytopenias were most strongly associated with ICU mortality, highlighting the importance of both disease-specific complications and baseline severity, and supporting the need for tailored prognostic tools and individualized management strategies.