Outcomes for Older Patients with Acute Myeloid Leukemia after Admission to the Intensive Care Unit (ICU)

Introductions: Older adults with acute myeloid leukemia (AML) have been shown to experience high health care utilization including ICU admissions. While risk factors for mortality have been identified for younger patients with AML admitted to the ICU, less is known about how older patients fare. We sought to examine the outcomes of older patients with AML following an ICU admission, and to identify predictors of ICU mortality.

Methods: We conducted a retrospective analysis of 330 consecutive patients ≥ 60 years diagnosed with AML between 2005 and 2011 at two hospitals in Boston. We examined rates of survival and functional recovery after ICU admissions using descriptive statistics. We used logistic regression to identify risk factors for higher in-hospital mortality after ICU admission.

Results: A total of 96/330 (29.1%) patients with AML ≥ 60 years were admitted to the ICU. The median age was 67 (range 60-88). The most common reasons for ICU admission were respiratory failure (38.7%), shock (36.6%), multi-organ failure (8.6%), and intracranial hemorrhage (4.3%). Approximately half of patients required vasopressors (46.9%, 45/96) or invasive ventilation (47.9%, 46/96). Overall, 57.3% (55/96) of patients survived ICU admission, and 45.8% (44/96) were eventually discharged from the hospital. A substantial minority of patients were alive at 30 days (42.7%, 41/96), 90 days (35.4%, 34/96), and one year (30.2%, 29/96) after ICU admission. Among patients who were alive at 90 days post ICU stay, 76.0% had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at that time; 74.9% were independent for all activities of daily living (ADLs), and 78.6% continued to receive AML-directed therapy. In a multivariate analysis, higher ECOG performance status prior to ICU admission (OR 2.52, P = 0.026), and receipt of two or more life-support modalities (i.e. vasopressors, invasive ventilation, and/or renal replacement therapy; OR = 14.3, P < 0.001) were associated with increased odds of in-hospital mortality. Age, comorbidities, gender, time from diagnosis, and receipt of stem cell transplantation were not associated with in-hospital mortality following ICU admission.

Conclusions: A substantial proportion of older patients with AML survive ICU admission with excellent functional outcomes. Poorer performance status prior to ICU admission and the need for two or more life-sustaining therapies were associated with higher in-hospital mortality. These data suggest that critically ill older patients with AML-especially those who do not require two or more life-sustaining therapies-often ultimately benefit from ICU admission.