Primary thromboembolic prevention in multiple myeloma patients: An exploratory meta-analysis on aspirin use

Background: Multiple myeloma (MM) is a common hematological disorder, often complicated by venous thromboembolism, especially during treatment with immunomodulatory drugs. Acetylsalicylic acid (ASA) has been extensively used as thromboprophylaxis but its rationale is unclear and the efficacy versus low-molecular weight heparins (LMWH) is still matter of debate. European and American guidelines suggest different approaches and the optimal antithrombotic strategy is yet to be established. Methods: We conducted an exploratory metanalysis and a systematic review on studies comparing ASA versus other interventions for thromboprophylaxis (no intervention or LMWH) in patients with MM. Results: Ten studies were included (2 randomized controlled trials, 6 longitudinal and 2 retrospective studies) with 1,964 participants (1,257 treated with ASA, 640 with LMWH and 67 with no thromboprophylaxis). Patients treated with ASA had a significantly lower risk of VTE compared to no intervention (OR=0.20; 95%CI: 0.07-0.61, p=0.005; I 2 =41%). The use of ASA was associated with a higher VTE risk compared to LMWH in longitudinal studies (OR=2.60; 95%CI: 1.08-6.25; p=0.03; I 2 =0%), however no differences have been showed in randomized controlled trials. Conclusions: ASA demonstrated a good efficacy compared to no intervention; data are insufficient to confirm superiority of LMWH over ASA as thromboprophylaxis in MM patients. Large and well powered trials are warranted. © 2017 Elsevier Inc.