Thromboembolic Complications in COVID-19 Patients Hospitalized in Italian Ordinary Wards: Data from the Multicenter Observational START-COVID Register.

 Coronavirus disease 2019 (COVID-19) infection causes acute respiratory insufficiency with severe interstitial pneumonia and extrapulmonary complications; in particular, it may predispose to thromboembolic disease. The reported incidence of thromboembolic complications varies from 5 to 30% of cases.  We conducted a multicenter, Italian, retrospective, observational study on COVID-19 patients admitted to ordinary wards, to describe the clinical characteristics of patients at admission and bleeding and thrombotic events occurring during the hospital stay.  The number of hospitalized patients included in the START-COVID-19 Register was 1,135, and the number of hospitalized patients in ordinary wards included in the study was 1,091, with 653 (59.9%) being males and 71 years (interquartile range 59-82 years) being the median age. During the observation, two (0.2%) patients had acute coronary syndrome episodes and one patient (0.1%) had an ischemic stroke; no other arterial thrombotic events were recorded. Fifty-nine patients had symptomatic venous thromboembolism (VTE) (5.4%) events, 18 (30.5%) deep vein thrombosis (DVT), 39 (66.1%) pulmonary embolism (PE), and 2 (3.4%) DVT+PE. Among patients with DVT, eight (44.4%) were isolated distal DVT and two cases were jugular thrombosis. Among patients with PE, seven (17.9%) events were limited to subsegmental arteries. No fatal PE was recorded. Major bleeding events occurred in nine (1.2%) patients and clinically relevant nonmajor bleeding events in nine (1.2%) patients. All bleeding events occurred among patients receiving thromboprophylaxis, more frequently when treated with subtherapeutic or therapeutic dosages.  Our findings confirm that patients admitted to ordinary wards for COVID-19 infection are at high risk for thromboembolic events. VTE recorded among these patients is mainly isolated PE, suggesting a peculiar characteristic of VTE in these patients.