The Risk of Venous Thromboembolism and Ischemic Stroke Stratified by VTE Risk Following Multiple Myeloma: A Korean Population-Based Cohort Study

Background: Multiple myeloma (MM) is associated with high morbidity and mortality, with elevated rates of arterial thrombosis and venous thromboembolism (VTE) and ischemic stroke (IS). We aimed to estimate the incidence of VTE and IS categorized by the VTE risk grade among individuals with MM in Korea. Additionally, we explored the potential of the IMPEDE VTE score as a tool for assessing IS risk in patients with MM. Methods: This retrospective cohort study comprised 37,168 individuals aged >= 18 years newly diagnosed with MM between January 2008 and December 2021 using the representative claims database of the Korean population. The risk of the incidence of VTE and IS within 6 months after MM diagnosis was stratified based on high-risk (IMPEDE VTE score >= 8) and low-risk (<8) categories. The hazard ratios (HRs) were estimated using Cox proportional hazard models. Results: The VTE incidence was 120.4 per 1000 person-years and IS incidence was 149.3 per 1000 person-years. Statistically significant differences were observed in the cumulative incidence rates of VTE between groups with high and low VTE scores (p < 0.001) and between individuals aged <= 65 years (p < 0.001) and those with a Charlson comorbidity index (CCI) >= 3 compared to lower scores (p < 0.001). Additionally, the cumulative incidence rate of IS differed significantly across all groups (p < 0.001). The HR for the high-risk group in VTE and IS occurrence was 1.59 (95% CI, 1.26-2.00) and 3.47 (95% CI, 2.99-4.02), respectively. Conclusions: It is important to screen and manage high-risk groups for the early development of VTE or IS in patients with newly diagnosed MM.