EMJ • June 2021 EMJ 70 Prevalence of Thromboembolic Complications in COVID-19 Infection: A Systematic Review and Meta-Analysis Abstract Introduction: The coronavirus disease (COVID-19) infection is proved to be involved in the onset of thromboembolism episodes. This study aims to evaluate the prevalence of thromboembolic complications in patients with COVID-19 from March until May 2020. Methods: A literature review was conducted in MEDLINE (via PubMed), Scopus, Embase, Cochrane, and CINHAL without any language and date of publication restriction (Prospero registration number CRD42020186925). The inclusion criteria were as following: 1) patients with diagnosis of COVID-19; 2) occurrence of thromboembolic event, and 3) patients older than 18 years of age. A multi-variable random efects model was computed accounting for correlations among outcomes by considering a heterogeneous compound symmetry covariance matrix. Results: Observational studies included 2,442 participants from 268 to 7,999 participants per study, 1,014 (41.52%) were male and 825 (33.78%) were female. The multi-variable pooled event rate of acute myocardial infarction was rare, estimated to be 0.03 (95% confdence interval [CI]: 0.00–0.07; p=0.23); this is also true for the meta-analytical estimate of disseminated intravascular disease which was 0.04 (95% CI: 0.00–0.08; p=0.03). Conversely, other events were found to be more frequent. Indeed, the pooled proportion of pulmonary embolism was 0.14 (95% CI: 0.08–0.20; p<0.001), while the venous thromboembolic event rate is 0.15 (95% CI: 0.09-0.30; p=0.04). The pooled intrahospital mortality rate was equal to 0.12 (95% CI: 0.08–0.16; p<0.001). Conclusions: Thromboembolic events, particularly venous thromboembolic event rate and pulmonary embolism, are a frequent complication in patients hospitalised with COVID-19. These fndings suggest that the threshold for clinical suspicion should be low to trigger prompt diagnostic Authors: *Valeria Pergola, 1 Honoria Ocagli, 2 Giulia Lorenzoni, 2 Danila Azzolina, 2,3 Loira Leoni, 1 Daniela Mancuso, 1 Chiara Palermo, 1 Marco Previtero, 1 Sabino Iliceto, 1 Dario Gregori, 2 Giovanni Di Salvo 4 1. Department of Cardiac, Thoracic and Vascular Sciences and Public Health, University of Padova, Padova, Italy 2. Unit of Biostatistics, Epidemiology and Public Health, Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, Padova, Italy 3. Department of Translational Medicine, University del Piemonte Orientale, Vercelli, Italy 4. Department of Women's and Children's Health, University of Padua, Padua, Italy *Correspondence to valeria.pergola@aopd.veneto.it Disclosure: The authors have declared no conficts of interest. Received: 10.10.20 Accepted: 27.02.21 Keywords: Coronavirus disease (COVID-19), systematic review, thromboembolism. Citation: EMJ. 2021;6[2]:70-80.