This study aims to assess whether reduced muscle mass is associated with an increased risk of bleeding in the elderly receiving direct oral anticoagulant therapy.

The researchers will compare the muscle mass of patients who experienced a hemorrhage (case) with that of patients who did not (control).

Muscle mass is a key criterion in the assessment of sarcopenia and malnutrition, two conditions frequently associated with aging. Sarcopenia is characterized by a significant loss of muscle mass and strength, while malnutrition is an alteration of nutritional status, often accompanied by sarcopenia, weight loss or a low body mass index (BMI). So at the same time, we want to compare sarcopenia and malnutrition between the two groups (case and control).

Cases and controls will benefit from a consultation during which measurements will be taken: weight, height, BMI, calf circumference, impedancemetry, etc. A blood test will be taken to measure anti-Xa activity (drug activity) and any missing analyses.

Inclusion Criteria:

• age of at least 70 years
• treated with one of the two factor Xa inhibitors used in France: Apixaban, Rivaroxaban.
• For cases : hemorrhagic event causing hospitalization
• For controls : free from hemorrhagic events.

Exclusion Criteria:

• Failure to obtain a consent form
• Patient under legal protection (guardianship, curatorship, or legal safeguard)
• Recurrent bleeding from a pre-existing lesion that has not received specific treatment. For example: unexplored gastrointestinal bleeding, cutaneous bleeding from a cancerous wound with therapeutic abstention.
• Bleeding caused by high-velocity trauma, surgery, or assault
• Contraindications to impedance measurement: pacemaker, cardiac defibrillator
• Elements that may provide erroneous impedance measurement data: bilateral limb amputation, bilateral joint replacements, dialysis.
• Unable to maintain the supine position.
• Digestive absorption disorder (celiac disease, short bowel, stoma, etc.)