Venous thromboembolism in hospitalized critical and non-critical COVID-19 patients: A systematic review andmetaanalysis

Background : Venous Thromboembolism has been observed as a frequent complication in patients with severe COVID-19 infection requiring hospital admission. Aims : To evaluate the epidemiology of venous thromboembolisms in hospitalized intensive care (ICU) and non-ICU patients. Methods : PubMed was searched up to 13 th of Nov 2020 and updated in December 12 th , 2020. We included studies that evaluated the epidemiology of VTE, including PE and/or DVT, in patients with COVID-19. See Figure 1. Results : A total of 91 studies reporting on 35,017 patients with COVID were included. The overall frequency of VTE in all patients, ICU and non-ICU was 12.8% (95% CI 11.103 to 14.605), 24.1% (95% CI 20.070 to 28.280), and 7.7% (95% CI 5.956 to 9.700), respectively. PE occurred in 8.5% (95% CI 6.911 to 10.208), and proximal DVT occurred in 8.2% (95% CI 6.675 to 9.874) of all hospitalized patients. The relative risk for VTE associated with ICU admission was 2.99 (95% CI 2.301 to 3.887, P value <0.001). DVT and PE estimates in studies that adopted some form of systematic screening were higher compared to studies with symptom-triggered screening. Analysis restricted to studies in the 5th quintile of sample size reported significantly lower VTE estimates. Conclusions : This study confirmed a high risk of VTE in hospitalized COVID-19 patients specially those admitted to the ICU. Nevertheless, sensitivity analysis suggests that previously reported frequencies of VTE in COVID-19 might have been overestimated.