PB0510 - Multiple Myeloma (MM) is Associated with an Increased Risk of Arterial Thromboembolic Events (ATE)

Background: Patients with newly diagnosed cancer have a 12-month cumulative incidence of ATE of 1-2% (Mulder et al., Leader et al.). Risk of venous thromboembolism in patients with cancer varies by cancer type. Whether risk of ATE also varies by cancer type in unknown.

Aims: We aimed to evaluate the incidence of ATE in patients with newly diagnosed MM starting treatment and determine if MM patients with ATE had a higher risk of mortality.

Methods: Using a nationwide cohort of US Veterans, we identified patients with newly diagnosed MM between 2006 and 2014 starting MM-treatment. ATE was defined as incident ischemic stroke and/or myocardial infarction within the first 12 months of MM-treatment using ICD codes as previously described. We analyzed the association between ATE and survival using a Cox proportional hazards model while adjusting for known confounders.

Results: Of the 2837 patients, mean age was 68.4 years. The mean number drugs included in first-line therapy was two, and 22% of patients received three or more drugs (dexamethasone counted as one drug). Consistent with the US veteran population, 97.7% of patients were male and 30.4% Black. The 6-month cumulative incidence of ATE for the cohort was 3.24% (95% CI 2.64-3.94) and the 12-month cumulative incidence was 4.83% (95% CI 4.08-5.66). ATE was associated with a 3-fold increased risk in mortality at 12 months after adjusting for known prognostic variables (Table 1).

Conclusion(s): In this cohort of 2837 patients with MM, the incidence of ATE was higher than reported in prior studies that included multiple cancer types. ATE in MM is associated with decreased survival after adjusting for potential confounders. Future studies should focus on identifying risk factors associated with ATE in MM as well as strategies to reduce this risk.