Venous Thromboembolism Risk in Patients With Cancer Receiving Chemotherapy: A Real-World Analysis

Introduction. The occurrence of malignant disease increases the risk for venous thromboembolism (VTE). Here we evaluate the risk for VTE in a large unselected cohort of patients with cancer receiving chemotherapy. Methods. The United States IMPACT health care claims database was retrospectively analyzed to identify patients with a range of solid tumors who started chemotherapy from January 2005 through December 2008. International Classification of Diseases, 9th revision, Clinical Modification Codes were used to identify cancer location, presence of VTE 3.5 months and 12 months after starting chemotherapy, and incidence of major bleeding complications. Health care costs were assessed one year before initiation of chemotherapy and one year after initiation of chemotherapy. Results. The overall incidence of VTE 3.5 months after starting chemotherapy was 7.3% (range 4.6%-11.6% across cancer locations) rising to 13.5% at 12 months (range 9.8%-21.3%). The highest VTE risk was identified in patients with pancreatic, stomach, and lung cancer. Patients in whom VTE developed had a higher risk for major bleeding at 3.5 months and at 12 months (11.0% and 19.8% vs. 3.8% and 9.6%, respectively). Health care costs were significantly higher in patients in whom VTE developed. Conclusion. Those undergoing chemotherapy as outpatients are at increased risk for VTE and for major bleeding complications. Thromboprophylaxis may be considered for such patients after carefully assessing the risks and benefits of treatment.