Incidence and predictors of venous thromboembolism (VTE) among ambulatory high-risk cancer patients undergoing chemotherapy in the United States.

BACKGROUND: Recent studies suggest that thromboprophylaxis is beneficial in preventing venous thromboembolism (VTE) in cancer outpatients, but this is not widely adopted because of incomplete understanding of the contemporary incidence of VTE and concerns about bleeding. Therefore, the authors examined the incidence and predictors of VTE in ambulatory patients with bladder, colorectal, lung, ovary, pancreas, or gastric cancers.

METHODS: Data were extracted from a large health care claims database of commercially insured patients in the United States between 2004 and 2009. Demographic and clinical characteristics of the cancer cohort (N = 17,284) and an age/sex-matched, noncancer control cohort were evaluated. VTE incidence was recorded during a 3-month to 12-month follow-up period after the initiation of chemotherapy. Multivariate analyses were conducted to identify independent predictors of VTE and bleeding.

RESULTS: The mean age of the study population was 64 years, and 51% of patients were women. VTE occurred in 12.6% of the cancer cohort (n = 2170) over 12 months after the initiation of chemotherapy versus 1.4% of controls (n = 237; P < .0001); incidence ranged by cancer type from 19.2% (pancreatic cancer) to 8.2% (bladder cancer). Predictors of VTE included type of cancer, comorbidities (Charlson Comorbidity Index score or obesity), and commonly used specific antineoplastic or supportive care agents (cisplatin, bevacizumab, and erythropoietin).

CONCLUSIONS: This large, contemporary, real-world analysis confirmed high rates of VTE in select patients with solid tumors and suggested that the incidence of VTE is high in the real-world setting. Awareness of the benefits of targeted thromboprophylaxis may result in a clinically significant reduction in the burden of VTE in this population.