Association of Inferior Vena Cava Filter Placement With Rates of Pulmonary Embolism in Patients With Cancer and Acute Lower Extremity Deep Venous Thrombosis.

Importance: Venous thromboembolism is the second overall leading cause of death for patients with cancer, and there is an approximately 2-fold increase in fatal pulmonary embolism (PE) in patients with cancer. Inferior vena cava (IVC) filters are designed to prevent PE, but defining the appropriate use of IVC filters in patients with cancer remains a substantial unmet clinical need. Objective: To evaluate the association of IVC filters with the development of PE in patients with cancer and deep venous thrombosis (DVT). Design, Setting, and Participants: A population-based cohort study was conducted using administrative data on 88 585 patients from the state inpatient databases for California (2005-2011) and Florida (2005-2014). Based on diagnostic and procedure codes, patients with cancer and acute lower extremity DVT were identified. All subsequent hospital visits for these patients were evaluated for the placement of an IVC filter, the development of new PE, the development of new DVT, and in-hospital mortality. Data analysis was performed from September 1 to December 1, 2019. Exposures: Placement of an IVC filter. Main Outcomes and Measures: The association of IVC filter placement with rates of new PE and DVT was estimated using a propensity score matching algorithm and competing risk analysis. Results: The study cohort comprised 88 585 patients (45 074 male; median age, 71.0 years [range, 1.0-104.0 years]) with malignant neoplasms who presented to a health care institution with a diagnosis of acute lower extremity DVT. Of these patients, 33 740 (38.1%) underwent IVC filter placement; patients with risk factors such as upper gastrointestinal bleeding (odds ratio, 1.32; 95% CI, 1.29-1.37), intracranial hemorrhage (odds ratio, 1.21; 95% CI, 1.19-1.24), and coagulopathy (odds ratio, 1.09; 95% CI, 1.08-1.10) were more likely to receive an IVC filter. A total of 4492 patients (5.1%) developed a new PE after their initial DVT diagnosis. There was a significant improvement in PE-free survival for these patients compared with those who did not receive IVC filters across the full, unbalanced study cohort as well as after propensity score matching and competing risk analysis (hazard ratio, 0.69; 95% CI, 0.64-0.75; P < .001). Furthermore, IVC filter placement reduced the development of PE in patients with very high-risk malignant neoplasms (eg, pancreaticobiliary cancer), high-risk malignant neoplasms (eg, lung cancer), and low-risk malignant neoplasms (eg, prostate cancer). After accounting for anticoagulation use and imbalanced risk factors, IVC filter placement did not increase the risk of new DVT development. Conclusions and Relevance: This study suggests that, for patients with cancer and DVT and bleeding risk factors, IVC filter placement is associated with an increased rate of PE-free survival.