A simplified scoring system to predict in-hospital mortality of leukapheresis in patients with leukemia.

6575 Background: The 2019 consensus guidelines from the American Society for Apheresis recommend leukapheresis as a category II recommendation (acceptable second-line therapy) for patients with symptomatic hyperleukocytosis or leukostasis. Mortality in these patients has been reported to vary between 8-29%. However, no tool is currently available to assess the mortality risk following the procedure. Methods: The National Inpatient Sample Database (2016-2021) and ICD-10 coding were utilized to identify adults (age ≥18 years) with leukemia who underwent leukapheresisprocedure. Different types of leukemia were identified along with various demographic and clinical characteristics of patients including symptoms of leucostasis such as acute encephalopathy, respiratory failure, cardiac failure, and renal failure using ICD-10 codes. Also included were complications associated with leukapheresissuch as hemorrhage. Multivariate logistic regression models were constructed to identify independent factors associated with mortality. A scoring system was constructed to identify the risks of mortality using the variables in the model and their associated odds ratio (OR). Splines were used to identify the knots which were used as cutoff values. The cumulative risk score was divided into three strata: low (mortality < 10%), intermediate (10-40%), and high risk (>40%). Results: Of the estimated 4,705 patients who underwent leukapheresis, 14.2% had lymphoid leukemia, 6.2% had monocytic leukemia, 52.2% had myeloid leukemia, and 3.6% had other types of leukemia. The overall in-hospital mortality was 24.2% and the median length of hospital stay was 10 days (IQR 5-24). 71.3% received leukapheresiswithin the first 48 hours of hospitalization. Variables identified as significantly associated with mortality included the type of leukemia: monocytic leukemia (OR 3.1), myeloid leukemia (OR 2.6), lymphoid leukemia (OR 1.8) other types of leukemia (OR 3.8). Organ failure associated with hospital mortality included acute respiratory failure (OR 12.7), acute renal failure (OR 2.3), cardiogenic shock (OR 8), acute encephalopathy (OR 2.2), and disseminated intravascular coagulation (OR 1.8). The cumulative mortality score ranged from 0 to 33, categorizing patients into high risk (score ≥ 5), intermediate risk (score 2-4) and low risk (score 0-1). The risk score demonstrated a performance with an area under the curve of 0.79. of note, age, gender, and race were non-contributory in this scoring system. Conclusions: A novel simplified scoring tool to predict in-hospital mortality in leukemia patients requiring leukapheresis is proposed. This tool can assist in preprocedural risk assessment and help guide management planning along with consideration for the role of other treatment modalities.