The risk of venous thromboembolism in adult patients with diffuse glioma: a nationwide population-based study.

Background and purpose: Venous thromboembolism (VTE) is a cause of increased morbidity and risk of death. Studies report VTE in up to 30% of glioma patients but the results vary. The VTE risk is relevant when evaluating prophylaxis to avoid unnecessary bleeding or overdiagnosis. This study examines the VTE incidence in patients with glioma WHO grade 2-4, and when VTE occurred, risk factors, and overall survival (OS) for patients with WHO grade 4.

Materials and methods: In total 3,630 patients with WHO grade 2 (n = 230), grade 3 (n = 317), and grade 4 (n = 3,083) gliomas from 2010 to 2018 were identified using the Danish Neuro-Oncology Registry. VTE diagnoses and time of death were obtained from Statistics Denmark.

Results and interpretation: The VTE incidence was 5.2, 6.3, and 6.8% in patients with WHO grade 2, 3, and 4 gliomas, respectively. The VTE incidence rate was highest during the first 3 months after the diagnosis with 53 events. Increasing age (HR 1.03, 95%CI 1.01-1.04), male sex (HR 1.47, 95%CI 1.09-1.99), poor performance status (HR 1.57, 95%CI 1.10-2.25), and post-operative long-course radiochemotherapy (HR 2.10, 95%CI 1.19-3.72) were predictors of VTE in patients with glioma WHO grade 4. There was no difference in OS comparing patients having VTE to those without (p = 0.068). In conclusion, patients with glioma WHO grade 2-4 were at high risk of VTE, especially the first 3 months after diagnosis. Increasing age, male sex, poor performance status, and long-course radiochemotherapy were associated with increased risk of VTE in patients with glioma WHO grade 4.