Elderly subjects are at greater risk of thrombophlebitis than the general population, but also of bleeding when anticoagulant therapy is initiated.

Enoxaparin is one of the most widely used anticoagulants in the management of venous thromboembolism in the world.

Its use is not codified in the elderly, because too few studies have been carried out in people over 75 years old.

For several years, Enoxaparin in curative treatment has been administered at a reduced dosage of 4000 IU twice a day (and not at a standard dose of 100 IU / kg) at the Geriatrics center of the CRHU in Strasbourg with the clinical impression of a reduction the risk of serious bleeding without reduction in therapeutic efficacy in this very elderly population.

Confirmation of a reduction in the risk of bleeding at this dosage could be the start of a change in prescribing practices, towards a more suitable dosage in the elderly.

Inclusion criteria:

• Subjects of age> = 75 years
• Having a weight> = 45kg for women and> = 57kg for men and a BMI <30, a GFR> 30 ml / min in Cockcroft-Gault, and having benefited from treatment with Enoxaparin for deep vein thrombosis and / or pulmonary embolism between 01/01/2000 to 11/30/2021.
• Subject having been informed by posting in the service and / or via the welcome booklet and not having expressed his opposition to the reuse of his data.

Exclusion criteria:

• Subject having expressed opposition to participating in the study
• History of heparin-induced thrombocytopenia in the last 100 days,
• condition associated with a high risk of bleeding such as congenital or acquired blood pathology,
• a recent hemorrhagic stroke,
• a gastrointestinal ulcer,
• the presence of a malignant tumor at high risk of bleeding, recent surgery of the brain, spine or ophthalmology, known or suspected oesophageal varices, arteriovenous malformations, a vascular aneurysm or major intraspinal or intracerebral vascular anomalies.

- Subjects of age> = 75 years and having a weight> = 45kg for women and> = 57kg for men and a BMI <30, a GFR> 30 ml / min in Cockcroft-Gault, and having benefited from treatment with Enoxaparin for deep vein thrombosis and / or pulmonary embolism between 01/01/2000 to 11/30/2021.