Pharmacologic Thromboprophylaxis Is Frequently Prescribed In Hospitalized Cancer Patients At Academic Medical Centers: A Prospective, Cross-Sectional, Multi-Center Study
Authors: Rojan Adam A. , Rehman Nadia Q. , Funches Renee E. , Campigotto Federico , Webster Jonathan , Connolly Gregory C. , Aggarwal Anita , Mobarek Dalia , Neuberg Donna S. , Wun Ted , Rickles Frederick , Streiff Michael B. , Khorana Alok A. , Zwicker Jeffrey I. 
Published: October 2019

Abstract

Background
Venous thromboembolism (VTE) is a frequent complication in hospitalized cancer patients and is associated with increased morbidity and mortality. Guidelines from major organizations recommend that all hospitalized patients with active malignancy receive pharmacologic thromboprophylaxis in the absence of bleeding or another contraindication. Nevertheless, reported rates of thromboprophylaxis use in hospitalized cancer patients have been low in several retrospective studies. We conducted a prospective cross-sectional study of hospitalized cancer patients at five academic hospitals to determine rates of thromboprophylaxis use and factors influencing the decision to administer thromboprophylaxis during hospitalization.

Methods
Administration of thromboprophylaxis to hospitalized cancer patients was assessed prospectively over consecutive days at five medical centers: University of Rochester, Johns Hopkins University, Beth Israel Deaconess Medical Center, University of California at Davis, and the DC Veterans Administration Medical Center/George Washington University. Data collected included reason for admission, cancer type and stage, and treatment as well as established risk factors for VTE including elements of the Padua Scoring System (PSS). The American College of Chest Physicians recommends the utilization of the PSS to guide thromboprophylaxis of hospitalized patients and a score of ≥4 is considered high risk for VTE. Univariate analysis for association of risk factors with the use of pharmacologic thromboprophylaxis was performed with two-sided Fisher exact tests and univariate logistic regression. Multivariable stepwise logistic regression model was performed to assess the influence of risk factors on the probability of receiving pharmacologic thromboprophylaxis.

Results
Seven-hundred and seventy-five patients were included in the study with a mean age of 56.3 years. Four hundred and thirty-five patients were male (56%) and 423 had hematologic malignancies (55%). The primary reason for admission was for cancer therapy in 254 cases (33%). Five hundred and eighty patients were considered high risk for VTE (≥4) using the PSS. Pharmacologic thromboprophylaxis was prescribed in 392 patients (51%, range 29%-71%). Accounting for contraindications to anticoagulation, 74% (N=528) of all cancer patients received appropriate hospital thromboprophylaxis. Among the cancer patients without contraindications for anticoagulation, individuals hospitalized with solid tumors were significantly more likely to receive thromboprophylaxis than those with hematologic malignancies (OR 2.34, 95% CI 1.43-3.82, P=0.0007). Cancer patients admitted for cancer-directed therapy (i.e. chemotherapy or radiation) were significantly less likely to receive thromboprophylaxis than those admitted for other medical conditions (OR 0.37 95% CI 0.22-0.61, P<0.0001). Sixty-three percent of low risk cancer patients as determined by PSS received anticoagulant thromboprophylaxis. Contraindications for anticoagulation were evident for the majority of the 383 patients (N=247, 64%) who did not receive pharmacologic thromboprophylaxis such as 161 with severe thrombocytopenia (42%), 43 with active hemorrhage (11%), 15 with a history of hemorrhage (4%), 2 with heparin induced thrombocytopenia (0.5%), and 11 on comfort-measure-only care (3%). Among the 136 patients who did not receive anticoagulation, 58.8% were considered high risk by the PSS.

Conclusions
This prospective, cross-sectional, multi-center study demonstrated that appropriate pharmacologic thromboprophylaxis is administered to the majority of hospitalized cancer patients. Despite absence of established benefit, the majority of lower risk cancer patients receive thromboprophylaxis during hospitalization.

Disclosures:
Wun: Daiichi-Sankyo: Research Funding. Rickles:Leo: Research Funding. Streiff:Bristol Myers Squibb: Research Funding; Sanofi: Consultancy, Honoraria; Eisai, Daiichi-Sankyo, Boehringer-Ingelheim, Janssen HealthCare: Consultancy. Khorana:Leo, Sanofi: Research Funding. Zwicker:Sanofi: Research Funding.