These sections briefly explain why we made the recommendations.
The panel acknowledged that there was a lack of good-quality evidence specific to people with COVID-19 and used their clinical knowledge and experience to build on the limited evidence base to develop the recommendations.
The panel agreed that all patients with COVID-19 pneumonia have an increased risk of VTE. Initial risk assessment for these patients should focus on identifying those whose bleeding risk contraindicates pharmacological VTE prophylaxis.
The NICE guideline on reducing the risk of VTE in over 16s in hospital (NG89) recommends pharmacological VTE prophylaxis for at least 7 days for acutely ill medical patients. The panel agreed that, in their experience, pharmacological VTE prophylaxis is often provided for less than the recommended 7 days in general medical patients, and emphasised the importance of following this recommendation for patients with COVID-19 pneumonia.
The panel indicated that, in their experience, a standard dose of pharmacological VTE prophylaxis is sufficient for most patients, but dose adjustments may be needed for patients at extremes of body weight and those with renal impairment. To ensure that all patients are given an appropriate dose, the panel included dose adjustment in their recommendation, adding that the summary of product characteristics and local protocols should be used to guide decisions on dose adjustment.
The panel agreed that parenteral anticoagulants offer benefits including fewer drug‑drug interactions, better absorption and ease of measurement, compared with oral anticoagulants.
There was limited evidence on extending VTE prophylaxis for patients who have been discharged after treatment for COVID-19 pneumonia. The panel made a recommendation for research on extending pharmacological VTE prophylaxis after discharge to explore the effectiveness and safety of extended pharmacological VTE prophylaxis for these patients.
The panel noted the high incidence of VTE in patients with COVID-19 pneumonia who need advanced respiratory support. There is some evidence available on the use of higher doses of anticoagulant for VTE prophylaxis in these patients. The panel, based on their experience, agreed that consideration should be given to increasing the standard prophylactic dose of parenteral anticoagulation, such as LMWH, to an intermediate dose to mitigate the increased risk of VTE while minimising the risk of bleeding associated with higher doses. The panel emphasised the importance of monitoring bleeding and other adverse events in patients with COVID-19 pneumonia who are given intermediate-dose anticoagulants. They also made a recommendation for research on standard-dose compared with intermediate-dose pharmacological VTE prophylaxis.
There was no evidence to inform recommendations on reducing the risk of VTE in patients with COVID-19 pneumonia managed in community settings with input from hospital clinicians, such as 'hospital at home' services or COVID-19 'virtual wards'. Patients managed in these settings have an increased risk of VTE that is similar to that of patients managed in hospital. The panel therefore included a recommendation to consider pharmacological VTE prophylaxis for these patients, to ensure they receive the same care as those admitted to hospital.
The panel also made a recommendation for research on extending pharmacological VTE prophylaxis after discharge in patients who have received treatment for COVID-19 pneumonia.
The panel noted the lack of evidence on pharmacological VTE prophylaxis for patients with COVID-19 and additional risk factors. They agreed that VTE risk in women with COVID-19 who are pregnant or have given birth in the past 6 weeks should be managed in line with advice on COVID-19 in pregnancy published by the Royal College of Obstetricians and Gynaecologists.
There was no evidence on pharmacological VTE prophylaxis for specific groups with additional risk factors for VTE, including people who are receiving treatment with sex hormones, have or have previously had cancer, are receiving renal replacement therapy or extracorporeal membrane oxygenation, have a clotting condition or history of venous thromboembolism, or have obesity (BMI 30 kg/m² or higher). The panel made a recommendation for research on standard-dose compared with intermediate-dose pharmacological VTE prophylaxis in people with COVID-19 who have additional risk factors for VTE.