D-dimer predicts venous thromboembolism in multiple myeloma: a nested case-control study

Background: Clinical risk assessment scores, such as IMPEDE VTE, can identify patients with multiple myeloma (MM) at high-risk of venous thromboembolism (VTE). Refinement of these scores, by including 1 or more biomarkers, could improve risk assessment. Objectives: We sought to determine the association between soluble P-selectin (sP-selectin) and D-dimer with VTE in MM. Methods: We identified 545 patients with newly diagnosed MM. Using a nested case-control design, we identified 38 cases of VTE within 6-months of MM treatment and 137 randomly selected controls. Using logistic regression, we examined the association between D-dimer and sP-selectin with VTE. We also analyzed the association after adjusting for IMPEDE VTE. Results: Each 1-point increase in IMPEDE VTE score was associated with a 27% increase in odds of VTE (odds ratio 1.27; 95% CI 1.08-1.51; c-statistic 0.61; 95% CI 0.51-0.71). There was no association between sP-selectin and VTE. Each one increase in natural log of D-dimer was associated with a 44% increase in odds of VTE, so we assigned points (ranging from −2 to +2) to D-dimer values and incorporated them into IMPEDE VTE, forming IMPEDED VTE. There was a 30% increase in odds of VTE per each 1-point increase in IMPEDED VTE (OR 1.30; 95% CI 1.12-1.52; c-statistic 0.65; 95% CI 0.55-0.75). Conclusion: Among patients with newly diagnosed MM starting chemotherapy, D-dimer was associated with increased odds of developing VTE within the subsequent 6-months. The addition of D-dimer to IMPEDE VTE—IMPEDED VTE—could improve prediction of VTE among patients with MM.