Prognosis

• cancer ^a
• impaired coagulation inhibition ^a
• a proximal DVT ^a
• a history of venous thromboembolism ^a

and reduced with 

• recent surgery ^a
• recent trauma or fracture ^a
• longer duration of anticoagulation

Cancer and clotting disorders increase the risk of venous thromboembolism

Patient	Prognostic Factor	Outcome	CER	OR (95% CI)	NNF+ (95% CI)
first DVT  a	cancer independent	recurrent venous thromboembolism at 2 years	18%	1.72 (1.31 to 2.25)	8 (5 to 19)
	impaired coagulation inhibition independent			1.44 (1.02 to 2.01)	14 (7 to 270)
DVT a	proximal DVT independent	recurrent venous thromboembolism at 5 years	20%	2.30 (1.55 to 3.42)	6 (4 to 13)
	history of venous thromboembolism independent			1.71 (1.16 to 2.52)	10 (5 to 41)
first DVT  a	recent surgery independent	recurrent venous thromboembolism at 2 years	18%	0.36 (0.21 to 0.62)	-7 (-13 to -5)
	recent trauma or fracture independent			0.51 (0.32 to 0.87)	-10 (-40 to -7)
DVT a	longer duration of anticoagulation  independent	recurrent venous thromboembolism at 5 years	20%	0.95 (0.92 to 0.98)	-130 (-310 to -80)