A randomized trial comparing 2 low-molecular-weight heparins for the outpatient treatment of deep vein thrombosis and pulmonary embolism.
BACKGROUND
Low-molecular-weight heparins (LMWHs) are now standard therapy for the treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE). No published trials have compared LMWHs, and few studies have examined outpatient therapy for PE. Only tinzaparin sodium has demonstrated superiority to unfractionated heparin in a clinical trial.


METHODS
We compared 2 LMWH products, tinzaparin and dalteparin sodium, for the treatment of acute DVT and PE in a randomized, controlled clinical trial of consecutive outpatients presenting to a venous thromboembolism service at 4 tertiary-care hospitals. Patients were treated with subcutaneous tinzaparin sodium, 175 IU/kg every 24 hours, or subcutaneous dalteparin sodium, 200 IU/kg every 24 hours, for at least 5 days. Warfarin sodium therapy was started simultaneously and continued for 90 days. The primary end point was efficacy (recurrence of venous thromboembolism); safety (bleeding) was a composite end point.


RESULTS
Two hundred fifty-four patients received tinzaparin (39 with PE and 215 with DVT) and 251 received dalteparin (51 with PE and 200 with DVT). Most patients had an active malignancy or idiopathic DVT/PE. The outcome events occurred in 11 (4.4%; 95% confidence interval [CI], 2.2%-7.7%) and 15 patients (5.9%; 95% CI, 3.3%-9.5%) in the dalteparin and tinzaparin groups, respectively, including 9 and 10 recurrences, respectively, and 2 and 5 major hemorrhages, respectively (P = .44). The 95% CI on the difference of -1.5% was -5.3% to 2.4%.


CONCLUSIONS
Tinzaparin and dalteparin are safe and effective for the outpatient treatment of DVT or PE. Our finding of no differences between the LMWHs based on major clinical end points means that practical issues can be the deciding factor on which drug to use.
Wells
Philip S
PS
Departments of Medicine, University of Ottawa, Ottawa Health Research Institute, Ottawa, Ontario. pwells@ohri.ca
Anderson
David R
DR
Rodger
Marc A
MA
Forgie
Melissa A
MA
Florack
Peggy
P
Touchie
Donna
D
Morrow
Beverly
B
Gray
Lisa
L
O'Rourke
Keith
K
Wells
George
G
Kovacs
Judy
J
Kovacs
Michael J
MJ
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000553:Ambulatory Care; D017985:Dalteparin / Q000627:therapeutic use*; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006495:Heparin, Low-Molecular-Weight / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000188:drug therapy*; D000078222:Tinzaparin; D016896:Treatment Outcome; D020246:Venous Thrombosis / Q000188:drug therapy*
D005343:Fibrinolytic Agents; D006495:Heparin, Low-Molecular-Weight; D000078222:Tinzaparin; D017985:Dalteparin