Anticoagulation prescribing practices in high-risk, under-represented patients with malignancy and venous thromboembolism (VTE).
Authors: Berardi Giuliana , Mao Anne , Berardi Antonio , Black Samuel , Chakraborty Anumita , Garver Megan , Graham Brianna , Rizwan Farsha , Keane Nicole 
Published: June 2023

e18532 Background: Incidence of VTE in cancer patients is 9x higher than the general population with higher rates amongst Black patients. Current published guidelines indicate that low molecular weight heparin be utilized first line; however, studies have found that oral anticoagulants are easier to use, offer a lower bleeding risk, and improve quality of life. Historically, these studies have < 10% minority populations and extensive exclusion criteria. Here we seek to determine anticoagulation (AC) prescribing patterns amongst a largely underserved, under-represented inner city population. Methods: Retrospective chart review was performed utilizing international classification of disease codes that consist of cancer, VTE and bleeding events. Patients recruited were age 18+ with cancer, hospitalized (inpatient, IP) or cared for at an outpatient appointment (outpatient, OP) at Temple University Hospital or Fox Chase Cancer Center between January 1, 2016 - December 1, 2021. Data extracted: demographics, cancer type, pertinent past medical history, weight, creatinine clearance (CrCl), type and dose of AC prescribed, adverse events, and subsequent VTE events. Following data extraction, manual chart review was performed to remove duplicates and verify accuracy of data. Results: 1060 patients were included (n = 529 OP, n = 531 IP). 45.2% minorities (n = 479/1060): 35.6% Black (n = 377/1060), 8.2% Hispanic (n = 87/1060), 1.1% Asian/Pacific Islander (n = 12/1060), 0.57% Native American/Eskimo (n = 6/1060). Average age was 65 years old. Average CrCl < 30 was 3.2% (n = 14/529 OP, n = 20/531 IP) with 70.6% prescribed apixaban (n = 15/20 IP, n = 9/14 OP). 15.6% of patients weighed < 60 kg and 40.3% of these patients were prescribed apixaban (n = 45/106 IP, n = 22/60 OP). 4.3% of patients weighed > 120 kg and 32.6% of these patients were prescribed apixaban (n = 9/18 IP, 6/28 OP). AC prescribing practices did not vary amongst IP and OPs. Apixaban (39%, n = 410/1060) was prescribed more frequently than enoxaparin (34.8%, n = 369/1060), followed by rivaroxaban (18.9%, n = 201/1060); then, a mix of other anticoagulants, including warfarin, edoxaban, fondaparinux, and dabigatran. Serious bleeding events that caused physicians to discontinue AC were most often found amongst patients prescribed rivaroxaban in OPs (5.63%, n = 8/142) and enoxaparin in IPs (7.07%, n = 15/212). Conclusions: We present the largest data set presently known in an under-represented IP and OP cancer population to better provide guidance when selecting AC. Apixaban appeared to be most often prescribed with the least amount of serious adverse bleeding effects requiring cessation of AC. Many patients did not meet apixaban prescribing criteria, (weight < 60 kg or > 120 kg; CrCl < 30) or had characteristics excluded from prior studies (ie, IVC filters, PORTs, PICCs) calling for further analysis regarding safety and adverse event profile.