Predicting venous thromboembolism in multiple myeloma: development and validation of the IMPEDE VTE score

Abstract

Abstract Venous thromboembolism (VTE) is a common cause of morbidity and mortality among patients with multiple myeloma (MM). The International Myeloma Working Group (IMWG) developed guidelines recommending primary thromboprophylaxis, in those identified at high‐risk of VTE by the presence of risk factors. The National Comprehensive Cancer Network (NCCN) has adopted these guidelines; however, they lack validation. We sought to develop and validate a risk prediction score for VTE in MM and to evaluate the performance of the current IMWG/NCCN guidelines. Using 4446 patients within the Veterans Administration Central Cancer Registry, we used time‐to‐event analyses to develop a risk score for VTE in patients with newly diagnosed MM starting chemotherapy. We externally validated the score using the Surveillance, Epidemiology, End Results (SEER)‐Medicare database (N = 4256). After identifying independent predictors of VTE, we combined the variables to develop the IMPEDE VTE score ( I mmunomodulatory agent; Body M ass Index ≥25 kg/m 2 ; P elvic, hip or femur fracture; E rythropoietin stimulating agent; D examethasone/Doxorubicin; Asian E thnicity/Race; V TE history; T unneled line/central venous catheter; E xisting thromboprophylaxis). The score showed satisfactory discrimination in the derivation cohort, c ‐statistic = 0.66. Risk of VTE significantly increased as score increased (hazard ratio 1.20, P = <.0001). Within the external validation cohort, IMPEDE VTE had a c‐statistic of 0.64. For comparison, when evaluating the performance of the IMWG/NCCN guidelines, the c‐statistic was 0.55. In summary, the IMPEDE VTE score outperformed the current IMWG/NCCN guidelines and could be considered as the new standard risk stratification for VTE in MM.