Thromboembolism Incidence and Risk Factors in Multiple Myeloma After First Exposure to Immunomodulatory Drug–Based Regimens

We evaluated time to thromboembolism (TE) and risk factors in multiple myeloma (MM) patients after first exposure to immunomodulatory therapy, stratified by thromboprophylaxis. We retrospectively analyzed adult MM patients who received immunomodulatory therapy with or without dexamethasone between February 2012 and October 2017. Thromboprophylaxis included aspirin, anticoagulants (low-molecular-weight heparin, direct oral anticoagulants, or warfarin), or none. Primary endpoint was time to on-treatment TE by thromboprophylaxis type. Time to TE using death as a competing risk censored at 12 months was used in univariate and multivariable analyses to identify risk factors. Of 485 evaluable patients, 57% were white and 36% African American; median age was 66. Most received lenalidomide (97.5%) and dexamethasone (90%). Half presented with ≥ 1 comorbidities. Sixty-nine had no documented receipt of prophylaxis, 357 aspirin, and 59 anticoagulation. More patients receiving anticoagulants had ≥ 1 comorbidities compared to aspirin or no-prophylaxis groups (P < .001). There was no difference in 12-month estimated cumulative incidence of TE (7.3%; 95% confidence interval, 5.2-9.9) between thromboprophylaxis groups (none 4.4%, aspirin 8.5%, anticoagulant 3.4%) (P = .24). In multivariable analyses, male sex (hazard ratio, 2.50; 95% confidence interval, 1.21-5.17; P = .014) and presence of any comorbidity (hazard ratio, 2.35; 95% confidence interval, 1.17-4.73; P = .016) were associated with TE incidence; thromboprophylaxis type was not (P = .12). Male sex and presence of any comorbidity were associated with time to TE. There were no differences in TE incidence between thromboprophylaxis groups despite a higher proportion of those in the anticoagulant group having ≥ 1 comorbidities. •Risk of thromboembolism is high in multiple myeloma.•Aspirin or stronger anticoagulants may mitigate this risk.•Male sex and/or presence of at least one comorbidity increased thromboembolism risk.•Stronger anticoagulants in those with ≥ 1 comorbidities should be considered. Data are lacking regarding incidence and risk for thromboembolism (TE) in myeloma, including receipt of thromboprophylaxis. In a single-center evaluation of 485 patients, male sex and presence of any comorbidity were associated with time to TE. Thromboprophylaxis type was not associated with incidence despite a higher proportion of those in the anticoagulant group having ≥ 1 comorbidities.