Validation of Risk-Adapted Venous Thromboembolism Prediction in Multiple Myeloma Patients.

Multiple myeloma (MM) is associated with an increased risk of venous thrombosis (VTE). In the United Kingdom Medical Research Council (MRC) XI study of patients treated with immunomodulatory therapy, the VTE rate was 11.8% despite 87.7% of the patients being on thromboprophylaxis at the time of thrombosis. In order to effectively prevent VTE events in MM patients, a better understanding of patient and disease risk factors that might predict thrombosis is required. We performed a retrospective cohort analysis of over 300 newly diagnosed MM patients at a tertiary referral centre to determine the VTE rate, predictive factors for VTE, value of the Khorana score for MM VTE events and long-term mortality outcomes. Fifty-four percent of the patients were receiving thromboprophylaxis at the time of the VTE event. The mortality odds ratio was 3.3 (95% CI, 2.4-4.5) in patients who developed VTE in comparison to age-matched controls with MM. A younger age at diagnosis and higher white cell count (WCC) were found to be predictive of VTE events. Our data suggest that standard thromboprophylaxis may not be effective in preventing VTE events in myeloma patients, and alternative strategies, which could include higher-intensity thromboprophylaxis in young patients with a high WCC, are necessary.