Impact of Venous Thromboembolism during High Intensity Chemotherapy for Acute Leukemia Patients on Duration of Hospital Stay

Background: Patients (pts) with hematologic malignancies have an increased risk of venous thromboembolism (VTE) events, driven by both the underlying cancer and cancer treatment. This risk exists even in acute leukemia (AL) in the setting of profound thrombocytopenia and coagulopathies, which can delay VTE diagnosis and complicate management. We evaluated the incidence of VTE in AL pts during an admission for chemotherapy and determined its effect on the duration of hospital stay and likelihood of intensive care unit (ICU) admission. Methods: All pts admitted to the Cleveland Clinic inpatient leukemia service with a diagnosis of acute myeloid (AML), lymphoblastic (ALL), or promyelocytic leukemia (APL) between January 1, 2013 and March 31, 2018 and treated with high-intensity chemotherapy were included. High intensity regimens for AML and APL included infusional cytarabine and an anthracycline with the addition of ATRA for latter and for ALL included Hyper-CVAD and CALBG regimens. Pts were excluded if they were admitted directly to the ICU or were transferred after initiating chemotherapy from another institution. Cases with VTE were defined using specific ICD-9-CM codes [451.1x, 451.2; 451.81, 453.1, 453.2, 453.8, 453.9, 415.1x; and, in addition, 997.2 or 997.3 when coupled with a secondary diagnosis of VTE]. All VTE cases identified through this strategy via an electronic medical record query were additionally validated on subsequent chart review. Pts with a diagnosis of VTE were matched 1:3 based on age, sex, race, and leukemia subtype to pts who did not experience VTE during the incident admission. Pts were also assessed for administration of prothrombotic agents, including: PEG-asparaginase, oral contraceptives, and tyrosine kinase inhibitors. The length of stay for the incident hospitalization and incidence of ICU admission were compared between pts who did and who did not experience VTE. Results: Of the 400 AL pts admitted to the inpatient leukemia service during the study period to receive high-intensity chemotherapy, 10 (2.5%) had a documented VTE during the admission. Baseline characteristics of the 1:3 matched cohorts (AL with and without VTE) are shown in Table 3. The median age of the AL pts who developed VTE was 54.5 years (range, 20-78 yrs), 60% were females, median platelet count at the time of VTE diagnosis was 117,900/mL [(range, 29-476,000/mL); 4 pts had platelet (plt) counts below 50,000/mL, 8 pts had plt below 100,000/mL; 2 pts had norm