Venous thromboembolism in critically-ill patients with pneumonia in the pre-COVID-19 era: Data from a large public database

Background: The high risk of venous thromboembolism (VTE) is a hallmark of COVID-19, particularly in intensive care units (ICU) patients. However, the magnitude of this risk is a matter of debate due to studies heterogeneity, significant changes on VTE management in COVID-19 era and scarce evidence of VTE risk in ICU patients with pneumonia in the pre-COVID-19 era. Aims: To evaluate the VTE risk in the pre-COVID-19 era in a large ICU database. Methods: Data of consecutive pneumonia patients admitted to ICU were retrieved from the Medical Information Mart for Intensive Care III (MIMIC-III) . VTE incidence during ICU stay was described. The association of thromboprophylaxis and VTE risk was determined by logistic regression, adjusted for age, sex, SOFA score, pneumonia diagnosis and type of ICU. Results: Among 6,842 pneumonia patients admitted to ICU, the median ICU stay was 11 (IQR 6-20) days. Tables 1 and 2 summarizes patients' characteristics and outcomes. 486 patients were diagnosed with VTE after a median of 3 (IQR 1-11) days in ICU. The overall cumulative incidence of VTE was 7% (95%CI 6.4-7.6), corresponding to a daily VTE incidence of 0.51% (95%CI 0.47-0.56). 1788 patients received thromboprophylaxis (out of 2958 for whom that data was available). The cumulative incidence of VTE was 10.7% (95%CI 8.9-12.6) among patients without thromboprophylaxis and 6.5% (95%CI 5.4-7.8) among those with thromboprophylaxis. Overall mortality was 19.3%, that was similar among patients with and without VTE (20.6% and 19.2%, respectively). (Table Presented) Conclusions: In pre-COVID-19 era, VTE rates in ICU patients with pneumonia was not substantially different from those reported in COVID-19 when VTE diagnosis is based on clinical suspicion. The risk of VTE was reduced by 46% with thromboprophylaxis. These findings can serve as comparator for future studies aiming at evaluating the impact of VTE on COVID-19.