Temporal Trends and Prognostic Factors in Critically Ill Adult Patients with Acute Leukemia: An Individual Participant Data Meta-Analysis

Purpose Critically ill patients with acute leukemia often require intensive care unit (ICU) admission. As major therapeutic advances have been made during the last decades, the aim of this study was to assess temporal trends in ICU mortality, and identify prognostic factors to inform clinician decision-making. Methods We conducted an individual participant data meta-analysis of studies including adults with acute leukemia admitted to the ICU. Patients with a history of allogeneic hematopoietic stem cell transplantation were excluded. Mixed-effects logistic regression models, accounting for center of ICU admission as a random variable, evaluated factors associated with ICU mortality, with particular focus on year of ICU admission, age (> 65 years) and invasive mechanical ventilation. Results A total of 2003 patients from 55 ICU across 19 countries were included (median age 58 years [IQR 44–67]; 72% acute myeloid leukemia [AML]; 64% admitted during induction chemotherapy). Invasive mechanical ventilation, vasopressors, and renal replacement therapy were required in 55%, 57%, and 21% of patients, respectively. Crude ICU mortality was 45% overall and 66% among ventilated patients. Age > 65 years was associated with higher ICU mortality (odds ratio (OR) 1.71 [95% CI, 1.31–2.23]). A diagnosis of AML (OR 1.65 [1.22–2.23]), admission during diagnosis or induction chemotherapy (OR 1.58 [1.16–2.13]), relapsed or refractory disease (OR 1.87 [1.25–2.79]), and the need for life-sustaining therapies (OR 6.97 [5.02–9.69]) were also associated with increased ICU mortality. Later admission period (after 2010) was associated with improved survival among ventilated patients only (OR 0.60 [0.37–0.98]). Conclusions In this large international individual participant meta-analysis, survival of critically ill patients with acute leukemia improved over time, particularly among those requiring mechanical ventilation. Age and the need for mechanical ventilation and other life-sustaining therapies remain strong, independent predictors of ICU mortality. Future work should integrate frailty and functional assessments to refine prognostic stratification and guide treatment intensity in this complex population. Trial registration The protocol was registered in PROSPERO (CRD420251046286).