Complications

Major bleeding is uncommon. ^b  
The risk is increased with

• age >72 ^a
• increasing aPTT levels ^a

Note:

• 6% of patients have a major bleed fall in haemoglobin > 2.0 g/dl, need for blood transfusion or intracranial or retroperitoneal bleed) (95% CI: 4% to 8%) ^b

Old age increases the risk of bleeding on heparin

Patient	Prognostic Factor	Outcome	CER	OR (95% CI)	NNF+ (95% CI)
proximal DVT a	aged >72 independent	bleed at 10 days	7.1%	1.61 (1.03 to 2.53)	53 (21 to 1100)