LAUSR

To the editor In-hospital patients with severe acute respiratory syndrome coronavirus 2-induced disease (COVID-19) have a high risk of thrombosis [1–4]. Pharmacological thromboprophylaxis is strongly encouraged, and several experts even suggest the use of high-dose prophylaxis or full anticoagulation for patients with severe disease at low risk of bleeding, but up to now, data on safety of this approach are lacking [1, 5–8]. Here, we report observational single-center prevalence of major bleeding events (ISTH definition, Table S1) in patients with COVID-19 receiving intensive thromboprophylaxis [9]. We included all consecutive adult patients with laboratoryproven COVID-19 treated between April 1st and May 6th 2020 at the Hospital La Carità, Locarno, Switzerland. On April 1st 2020, we have implemented the following intensive thromboprophylaxis scheme: Patients with COVID-19 with an estimated glomerular filtration rate (eGFR) ≥ 30 ml/ min/1.73 m2 received subcutaneous enoxaparin twice daily (BID) at a dose of 40 mg (< 80 kg), or 60 mg (≥ 80 kg) for a minimum of 14 days (dose level 1). Dose escalation to 60 mg BID (< 80 kg), or 80 mg BID (≥ 80 kg) was discussed if D-dimer levels increased during follow-up > 2.0 mg/L, irrespective of the presence of thromboembolic complications (dose level 2). Patients with COVID-19 with an eGFR < 30 ml/min/1.73 m2 received subcutaneous UFH at a dose of 5000 IU three times a day in the regular ward, or continuous intravenous UFH in the intensive care unit (ICU) with a target anti-Xa activity of 0.3–0.5 U/ml. The study was approved by the Ethical Committee Ticino, Switzerland (2020-00838 RIF.CE 3621). A total of 270 inpatients with confirmed COVID-19 were eligible for this analysis. 22 (8.2%) patients received regular thromboprophylaxis with once daily enoxaparin 40 mg or UFH 5000 IU two times a day, 183 (67.8%) patients received the intensified thromboprophylaxis, and 65 (24%) patients had full anticoagulation (Table 1). Of the 65 patients with therapeutic anticoagulation, 20 Bernhard Gerber and Marco Previsdomini contributed equally and are listed alphabetically.