Patients with Acute Myeloid Leukemia Admitted to Intensive Care Units: Outcome Analysis and Risk Prediction

Abstract

Background: This retrospective, multicenter study aimed to reveal risk predictors for mortality in the intensive care unit (ICU) as well as survival after ICU discharge in patients with acute myeloid leukemia (AML) requiring treatment in the ICU.

Methods and results: Multivariate analysis of data for 187 adults with AML treated in the ICU in one institution revealed the following as independent prognostic factors for death in the ICU: arterial oxygen partial pressure below 72 mmHg, active AML and systemic inflammatory response syndrome upon ICU admission, and need for hemodialysis and mechanical ventilation in the ICU. Based on these variables, we developed an ICU mortality score and validated the score in an independent cohort of 264 patients treated in the ICU in three additional tertiary hospitals. Compared with the Simplified Acute Physiology Score (SAPS) II, the Logistic Organ Dysfunction (LOD) score, and the Sequential Organ Failure Assessment (SOFA) score, our score yielded a better prediction of ICU mortality in the receiver operator characteristics (ROC) analysis (AUC = 0.913 vs. AUC = 0.710 [SAPS II], AUC = 0.708 [LOD], and 0.770 [SOFA] in the training cohort; AUC = 0.841 for the developed score vs. AUC = 0.730 [SAPSII], AUC = 0.773 [LOD], and 0.783 [SOFA] in the validation cohort). Factors predicting decreased survival after ICU discharge were as follows: relapse or refractory disease, previous allogeneic stem cell transplantation, time between hospital admission and ICU admission, time spent in ICU, impaired diuresis, Glasgow Coma Scale <8 and hematocrit of ≥25% at ICU admission. Based on these factors, an ICU survival score was created and used for risk stratification into three risk groups. This stratification discriminated distinct survival rates after ICU discharge.

Conclusions: Our data emphasize that although individual risks differ widely depending on the patient and disease status, a substantial portion of critically ill patients with AML benefit from intensive care.

Fig 1. Odds ratio (OR) plot of parameters associated with mortality in the ICU (intensive care unit).

Abbreviations: paO2, arterial oxygen partial pressure <72 mmHg at ICU admission.

Fig 2. Correlation of predicted versus actual ICU mortality (intensive care unit) in the training cohort.

(A) Receiver operator characteristics for the different scores with the area under the curve (AUC). Score 1: novel mortality score. Score 2: SAPS II. Score 3: LOD. Score 4: SOFA. (B) Predicted versus actual ICU mortality. Patients were classified according to their individual predicted ICU mortality (below versus ≥50%; boxes represent the interquartile range (IQR); whiskers indicate the minimum and maximum values but are not longer than 1.5 times the length of the corresponding box; values outside this range are represented by separate dots), which is plotted against the actual mortality rate for the three groups.

Fig 3. Correlation of predicted versus actual ICU mortality (intensive care unit) in the validation cohort.

(A) Receiver operator characteristics for the different scores with the area under the curve (AUC). Score 1: novel score. Score 2: SAPS II. Score 3: LOD. Score 4: SOFA. (B) Predicted versus actual ICU mortality. Patients were classified according to their individual predicted mortality in the ICU (below versus ≥50%; boxes represent the IQR; whiskers indicate the minimum and maximum values, but are not longer than 1.5 times the length of the corresponding box; values outside this range are represented by separate dots), which is plotted against the actual mortality rate.

Fig 4. Hazard ratio (HR) plot of parameters associated with survival after ICU (intensive care unit) discharge.

Abbreviations: SCT, stem cell/bone marrow transplantation; GCS, Glasgow Coma Scale; Hkt, hematocrit.

Fig 5. Correlation of predicted survival rate after ICU (intensive care unit) discharge with overall survival.

Patients were grouped according to their probability of survival and the corresponding Kaplan-Meier estimates. (A) Overall survival for patients in the training cohort. (B) Overall survival for patients in the validation group.