Clinical Prediction Rule of Louzada et al for Recurrent Thromboembolism in a Patient with Cancer-Associated Venous Thromboembolism (Ottawa Thromboembolism Rule)
Louzada et al reported a simple score for predicting recurrent venous thromboembolism (VTE) in a patient with cancer-associated venous thromboembolism. The authors are from University of Western Ontario, University of Ottawa, University of Manitoba, University of British Columbia, and Hopital Europeen Georges Pompidou (Paris).
Parameters:
(1) sex
(2) type of cancer
(3) TNM status for a solid tumor
(4) history of previous venous thromboembolism
Parameter
Finding
Points
sex
male
0
female
1
type of cancer
lung
1
breast
-1
other
0
TNM stage
Stage I
-2
Stage II, III or IV
0
previous VTE
no
0
yes
1
where:
• Den Exter et al modified the score by dividing TNM stage into I and II vs III and IV. They also recognized 3 risk levels (<= -1, 0, and >=1).
total score =
= SUM(points for all 4 parameters)
Interpretation:
• minimum score: -3
• maximum score: 3
• The higher the score the greater the risk for recurrent VTE.
Score
Risk of Recurrent VTE
Recurrent VTE
<= 0
low
<= 4.5%
>= 1
high
>= 19%
Score
Recurrent VTE (Table 3)
-2 or -3
0%
-1
4-5%
0
5-10%
1
13-16%
2
18%
3
25-50%
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