Outcomes in AML Patients Admitted to the ICU Following Allogeneic Stem Cell Transplantation
Authors: Mushtaq Ali , Dhakal Aastha , Hanna John , Sheu Michael , Anwer Faiz , Yetmar Zachary , Crilley Thomas Andrew , Asif Muhammad Anns , Majeed Aneela 
Published: December 2024

Background:
Patients with acute myeloid leukemia (AML) who undergo an allogeneic stem cell transplant (allo-SCT) frequently require admission to the intensive care unit (ICU) within the first 100 days post-transplant, which is often associated with a poor prognosis. This retrospective study aims to evaluate the clinical outcomes and infection epidemiology among patients who require ICU admission during this critical period.
Methods:
We screened 438 AML patients who underwent allo-SCT between 2012 and 2023, including adult patients ≥ 18 years old, within 100 days of their index transplantation who required ICU admission for more than 72 hours. 65 patients met these criteria. Patients were divided into sepsis (N=46) and non-sepsis (N=19) groups, and baseline characteristics, treatment regimens, and outcomes were compared. Univariable Cox regression was used to assess factors associated with 90-day mortality after ICU admission.
Results:
The median age was 56.8 years in the sepsis group and 63.9 years in the non-sepsis group, with males comprising 43.5% and 57.9%, respectively. The median time from transplant to ICU admission was 20 days. Graft-versus-host disease (GVHD) was more prevalent in the sepsis group (34.8% vs. 26.3%, p=0.5072), with 64.3% of GVHD patients receiving methylprednisolone. Both groups received comparable GVHD and antimicrobial prophylaxis. Patients with sepsis had a significantly higher rates of mechanical ventilation (67.4% vs. 15.8%, p&lt;0.001), longer ventilator duration (7.0 days vs. 2.0 days, p=0.03), vasopressor requirement (69.6% vs. 15.8%, p=&lt;0.001), and extended ICU stays (median 9.5 days vs. 3.0 days, p&lt;0.001).
Among septic patients, survivors (N=8) had fewer comorbidities and higher rates of GVHD (50% vs. 31.6%, p=0.421) compared to those who died (N=38). We found no significant differences in comorbidities, neutropenia, lymphocyte count, GVHD prophylaxis, or antimicrobial prophylaxis between survivors and non-survivors. Sepsis before engraftment was more common in survivors (71.4% vs. 61.8%), with no significant differences in lactate levels (3.3 vs. 2.7).
Overall, 52 patients (80%) died within 90 days of ICU admission. Univariable analyses revealed that sepsis (hazard ratio [HR] 3.34, 95% confidence interval [CI] 1.47-7.57; p=0.004), renal replacement therapy (HR 2.35, 95% CI 1.23-4.48; p=0.010), and mechanical ventilation (HR 3.14, 95% CI 1.61-6.12; p&lt;0.001) were associated with increased 90-day mortality, while GVHD was not significantly associated (HR 1.25, 95% CI 0.65-2.39; p=0.506). Lastly, there were no significant differences in infection types or antimicrobial usage between the sepsis and non-sepsis groups. The most identified organisms were Klebsiella, Enterococcus, and Pseudomonas, with no significant differences between survivors and non-survivors.
Conclusion:
Sepsis significantly worsens clinical outcomes in AML patients undergoing allo-SCT, leading to higher rates of mechanical ventilation, prolonged ICU stays, and increased 90-day mortality. Early identification and aggressive management of sepsis are essential for improving mortality outcomes in this high-risk population.