Unfractionated Heparin vs Low Molecular Weight Heparin for Acute Thromboembolism

SQ unfractionated heparin is as efficacious for acture thromboembolism as low-molecular weight venous thromboembolism is as effective for initial treatment of acute venous thromboembolism as is low-molecular weight heparin.

Citation/s:

Lead author's name and fax: Kearon, C.

Three-part Clinical Question: Is fixed-dose, weight-adjusted. subcutaneous unfractionated heparin as effective and safe as low-molecular weight heparin for treatment of venous thromboembolism?
Search Terms: venous throboembolsim, low-molecular weight heparin, unfractioned heparin

The Study:
Non-blinded randomised controlled trial without intention-to-treat.
The Study Patients: 18 years or older Acute venous thromboembolism No shock or major surgery in past 24 hours life expectancy of greater than 3 months Not receiving long term anticoagulation creatinine less than 2.4 mg/dL
Control group (N = 353; 352 analysed): Low molecular weight heparin at 100 IU/kg for 5 days or until INR was 2.0 or higher for 2 consecutive days.
Experimental group (N = 355; 345 analysed): Unfractionated heparin first dose of 333U/kg followed by 250 U/kg for 5 days or until INR was 2.0 or higher for 2 consecutive days.

The Evidence:
Outcome Time to Outcome CER EER RRR ARR NNT
Recurrent venous thromboembolism 0.034 0.037 -9% -0.003 -333
95% Confidence Intervals: -89% to 71% -0.030 to 0.024 NNT = 41 to INF; NNH = 33 to INF
Major bleed 0.034 0.017 50% 0.017 59
95% Confidence Intervals: -18% to 100% -0.006 to 0.040 NNT = 25 to INF; NNH = 161 to INF
major or minor bleeding 0.085 0.082 4% 0.003 333
95% Confidence Intervals: -44% to 51% -0.038 to 0.044 NNT = 23 to INF; NNH = 26 to INF

Non-Event Outcomes Time to outcome/s Control group Experimental group P-value
Death 18 22

Comments:
While this study does not address long term treatment of thromboembolism with unfractionated SQ heparin, it does provide evidence for initial treatment. More studies need to be conducted.

Appraised by: Jim Bridges 1718 Patterson ST Nashville, TN 37203 ; Monday, April 09, 2007
Email: jbridges@alivehospice.org
Kill or Update By: April 11, 2008