| Acute medical risk factors |
| Acute medical illnesses, eg acute myocardial infarction, heart failure, respiratory failure, acute infectious disease |
| Active cancer |
| Treatment for cancer (hormonal, chemotherapy, radiotherapy) |
| Inflammatory bowel disease |
| Nephrotic syndrome |
| Myeloproliferative disorders |
| Paroxysmal nocturnal haemoglobinuria |
| Central venous catheter |
| Vena caval filter |
| Immobility |
| |
| Permanent risk factors |
| Advanced age |
| Obesity |
| Varicose veins |
| Previous venous thromboembolism |
| Oestrogen‐containing oral contraception or hormone replacement therapy |
| Paresis |
| Inherited or acquired thrombophilia |
