Prognostic significance of thromboembolism in multiple myeloma: a systematic review and meta-analysis

Background: This study sought to investigate the clinical characteristics and prognosis of thromboembolism in multiple myeloma (MM). Methods: The PubMed, Embase, Web of Science, Wanfang, and China National Knowledge Infrastructure databases were systematically searched to retrieve relevant articles from the establishment of the databases to May 2022. This meta-analysis was performed to investigate the relationship between thromboembolism and overall survival (OS), progression-free survival (PFS), event-free survival (EFS), and mortality in MM patients. The meta-analysis of the included studies was performed using Revman5.3 software after quality evaluation. Results: A total of 9 studies from 7 articles, which included 38,047 MM patients and 6,412 cases of thromboembolism in the analysis. The levels of beta 2 microglobulin affected the occurrence of thromboembolism in MM patients [standard mean difference (SMD) =-0.09, 95% confidence interval (CI): -0.18 to - 0.01, P=0.02]. Venous thromboembolism (VTE) predicted poorer OS [hazard ratio (HR) = 0.79, 95% CI: 0.64-0.98, P=0.03] and higher early mortality (HR =2.27, 95% CI: 1.26-4.08, P=0.006) in MM. There was no significant difference in PFS/EFS (HR =0.81, 95% CI: 0.64-1.01, P=0.06) between thrombosis/embolism and non-thrombotic embolism. Arterial thrombosis was associated with significantly higher risk of death at 5 years (HR = 1.89, 95% CI: 1.33-2.69, P<0.01). Conclusions: beta 2 microglobulin levels were associated with VTE in MM. MM patients with VTE were more likely to have poorer prognosis and higher mortality rate than those without VTE. MM patients with arterial thromboembolism had higher 5-year mortality rate than those without arterial thromboembolism.