A newly developed and validated risk prediction score for venous thromboembolism (VTE) in multiple myeloma (MM), IMPEDE VTE, outperformed current guidelines for stratifying patients, according to results from a study published in the American Journal of Hematology.

Patients with MM experience a much greater risk of developing VTE compare with the general population, and VTE is a persistent cause of morbidity and mortality in these patients. Even though the International Myeloma Working Group (IMWG) created guidelines for patients with MM identified as being at high risk of developing VTE (recommending primary thromboprophylaxis) and the National Comprehensive Cancer Network (NCCN) implemented these guidelines, these guidelines have not been validated.

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In this study, researchers first developed a risk prediction score for VTE in patients with newly diagnosed MM by executing time-to-event analyses on data from 4446 patients in the Veterans Administration Central Cancer Registry. Data from the identified patients were assessed starting from when the patients were preparing to initiate chemotherapy. Identified patients were diagnosed with MM between September 1999 and June 2014, and patients who did not initiate chemotherapy within 6 months of diagnosis were excluded.

The c-statistic enabled assessment of discrimination as well as competing risk analysis, which allowed quantification of the association between risk score and the development of VTE. This study aligned with IMWG/NCCN guidelines in defining scores of 0 to 1 as low-risk and 2 or greater as high-risk. This study also defined patients who received NCCN high-dose multiagent chemotherapy (excluding bortezomib), dexamethasone, or doxorubicin combined with immunomodulatory treatment as high-risk.

Independent predictors of VTE included body mass index of 25 kg/m2 or greater; use of erythropoietin-stimulating agents; Asian ethnicity or race; use of immunomodulatory agents; prior history of VTE; pelvic, hip, or femur fractures; tunneled line or central venous catheters; use of dexamethasone or doxorubicin; and ongoing thromboprophylaxis. These were incorporated into the development of the IMPEDE VTE score.

By using the Surveillance, Epidemiology, End Results (SEER)-Medicare database, researchers externally validated IMPEDE VTE in 4256 patients. They also evaluated the current IMWG/NCCN guidelines using patients with MM who received immunomodulatory therapy. With a c-statistic of 0.64 in the SEER-Medicare database, compared with a c-statistic of 0.55 for the IMWG/NCCN guidelines, IMPEDE VTE was found to outperform the current guidelines.

The authors explained that “risk assessment can help clinicians select thromboprophylaxis in high-risk patients and avoid anticoagulants in those at low risk [of developing VTE]. These data suggest that the IMPEDE VTE score could replace the risk stratification within the current guidelines for identification of patients with MM at high risk for VTE.”

Reference

1. Sanfilippo KM, Luo S, Wang TF, et al. Predicting venous thromboembolism in multiple myeloma: development and validation of the IMPEDE VTE score [published online August 4, 2019]. Am J Hematol. doi:10.1002/ajh.25603