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Mortality rates high for patients with AML admitted into ICU
Adults with acute myeloid leukemia who were admitted into the ICU had a higher mortality rate and cost burden and longer length of stay than those hospitalized but not admitted into ICUs, according to results of a cohort study published in JAMA Oncology.
“This study has clear clinical implications and provides opportunities for improved, more personalized, supportive care and clinical outcomes among patients with AML,” Gary H. Lyman, MD, codirector of the Fred Hutchinson Institute for Cancer Outcomes Research at University of Washington, told HemOnc Today. “But the work is just beginning, as it will be critical to consider the multiple drivers of ICU admission and inpatient mortality together in validated risk prediction models that can be applied at the point of care for strategically optimizing supportive care resources, as well as provide for improved communication of risks and benefits to patients and their families.”
The survival of adults with AML has gradually improved during the last 4 decades; however, increased exposure to contemporary high-intensity therapies carries the risk for requiring ICU care.
“Understanding relevant risk factors for admission to the ICU and short-term mortality, which we did in the study, is an essential step in identifying patients with AML at high risk for adverse events,” Anna B. Halpern, MD, hematology/oncology fellowship program at the Fred Hutchinson Cancer Research Center told HemOnc Today. “This understanding will now allow for the development of preemptive strategies aimed at optimizing treatment outcomes and reducing the economic consequences of AML therapy.”
Admission to ICU and inpatient mortality among patients requiring ICU care served as primary outcomes. Secondary outcomes included ICU and total hospitalization length of stay and cost.
Researchers extracted information from the University HealthSystem Consortium database on 43,249 adults with AML (mean age, 59.5 years; standard deviation, 16.6) who were hospitalized for any cause between Jan. 1, 2004, and Dec. 31, 2012.
Of those patients, 26.1% were admitted to ICUs and 73.9% were not. Those admitted into ICUs had a mean stay of 22.4 days, compared with 15.3 days for those who were not.
On a multivariable analysis, researchers reported independent risk factors for admission to the ICU included age younger than 80 years (HR = 1.56; 95% CI, 1.42-1.70); hospitalization in the south (HR = 1.81; 95% CI, 1.71-1.92); hospitalization at a low- or medium-volume hospital (HR = 1.25; 95% CI, 1.19-1.31); number of comorbidities (HR for 5 vs. 0 = 10.64; 95% CI, 8.89-12.62); sepsis (HR = 4.61; 95% CI, 4.34-4.89); invasive fungal infection (HR = 1.24; 95% CI, 1.11-1.39); and pneumonia (HR = 1.73; 95% CI, 1.63-1.82).
In-hospital mortality was greater among patients in ICU care compared with those not in the ICU (43.1% vs. 9.3%).
Results of a multivariable analysis showed independent risk factors for death in patients requiring ICU care as age older than 60 years (HR = 1.61; 95% CI, 1.06-1.26); nonwhite/race ethnicity (HR = 1.18; 95% CI, 1.07-1.30); hospitalization on the West coast (HR = 1.19; 95% CI, 1.06-1.34); number of comorbidities (HR for 5 vs. 0= 18.76; 95% CI, 13.7-25.67); sepsis (HR = 2.94; 95% CI, 2.70-3.21); invasive fungal infection (HR = 1.20; 95% CI, 1.02-1.42); and pneumonia (HR = 1.13; 95% CI, 1.04-1.24).
Halpern and colleagues also reported mean costs of hospitalization were higher for AML patients requiring ICU care than those who did not ($83,354 vs. $41,973). Those costs increased with each comorbidity, from $50,543 for patients with no comorbidities to $124,820 for those with five or more.
Mean costs also were greater among patients admitted to ICUs in high-volume hospitals compared with low-volume hospitals ($96,979 vs. $67,195) and ICUs on the West coast compared with in the South ($108,918 vs. $72,588).
A univariate analysis indicated the mean length of stay in ICUs was longest at high-volume hospitals (23.8 days vs. 19.4 days) and on the West coast (25.3 days vs. 22 days; P < .001 for both).
Halpern and colleagues also noted that although they observed a decrease in hospital mortality in patients with AML during their study period — from 19.5% in 2004 to 14.5% in 2012 — this decrease was almost entirely driven by reduced early mortality in patients not requiring ICU care.
“I was surprised that ICU admission remains so common for patients with AML and that the mortality for these patients once admitted to the ICU remains very high and has not improved over the last decade, despite both decreases in the mortality for AML population not requiring ICU care, as well as advances in supportive care and critical care techniques for hematologic malignancies,” Halpern said. “I was also surprised at the large impact a patient's comorbidity burden had on their risk for ICU admission and mortality, as well as its large effect on cost. Also striking was how high costs in general were for AML patients requiring ICU care and how much they have risen over the last decade.”
Researchers noted patients with AML who were hospitalized more than once during the study period were counted for only one hospital visit, which may have led to an underestimate of true resource use because patients with AML often are readmitted in short time spans for treatment-related complications,” Halpern said. – by Chuck Gormley
For more information:
Anna B. Halpern, MD , can be reached at halpern2@uw.edu.
Gary H. Lyman, MD , can be reached at glyman@fredhutch.org.
Disclosure: Lyman and Halpern report no relevant financial disclosures. Please see the full study for a list of all other financial disclosures.