Risk factors for venous thromboembolism in elderly patients with glioblastoma.

Abstract

e13031 Background: Venous thromboembolism (VTE) is a common complication in glioblastoma (GBM) patients. Physicians are reluctant to administer anticoagulants to GBM patients with VTE, particularly to the elderly patients. Methods: After obtaining IRB approval, the Cleveland Clinic Brain Tumor and Neuro-Oncology Center’s database was used to identify patients with histologically confirmed GBM who were diagnosed with VTE and were ≥65 years of age at the time of diagnosis of GBM. Bivariate comparison of demographic and clinical features was performed by occurrence of DVT, using t-test for continuous data and fishers exact test for categorical variables. Multivariate proportional hazard model was developed adjusting for number of comorbidities (none, 1, 2-3, >3), Karnofsky Performance Status (KPS) at presentation (>70, ≤70), age (>75, ≤75), race, treatment (chemotherapy, radiation therapy, tumor resection). All p-values were 2-sided and were considered significant when <0.005. Results: Chart records of 517 patients diagnosed between 1990 and 2010 were included for analysis. Among 517 cases, 99 patients (54% male, median age at presentation 72 years, range 65-92 years) developed VTE. Median follow-up was 6.58 ± 9.58 months. Eighty-nine (90.8%) cases were diagnosed within 3 months of craniotomy. On univariable analysis, risk factors for VTE included lower KPS (HR 0.98, CI 0.96– 0.99, p = 0.001), thalamic tumors (HR 3.11, CI 1.14– 8.50, p = 0.027), and lower extremity paresis (HR 2.24, CI 1.46-3.46, p < 0.0001). Caucasian patients had a lower trend for developing VTE, however this was not statistically significant. On multivariable analysis, lower KPS was found to be related with higher incidence of VTE (HR 0.35, CI 0.18 – 0.66, p = 0.001). Conclusions: Lower KPS is associated with higher incidence of VTE. Further studies are needed to determine risk stratification and whether the use of medical prophylaxis after neurosurgical intervention can lead to decrease in the rates of VTE in elderly GBM patients.