Management of acute proximal deep vein thrombosis: pharmacoeconomic evaluation of outpatient treatment with enoxaparin vs inpatient treatment with unfractionated heparin.

OBJECTIVES

A landmark Canadian randomized controlled clinical trial compared treatment of acute proximal vein thrombosis via low-molecular-weight heparin (LMWH) [enoxaparin] administered primarily at home with IV unfractionated heparin (UH) in the hospital. Results demonstrated equivalent safety and efficacy for home care with enoxaparin with a reduction in cost. Our objective was to validate these findings in the routine practice setting of a US health maintenance organization.

DESIGN

Retrospective analysis of medical and administrative records of health-plan members meeting inclusion-exclusion criteria of the Canadian trial during the period from 1995 to 1998.

SETTING

Staff-model health maintenance organization serving New Mexico.

PATIENTS

Persons presenting as outpatients from 1995 to 1996 or from 1997 to 1998 with acute, proximal deep vein thrombosis (DVT) diagnosed by duplex ultrasonography.

INTERVENTIONS

Initial anticoagulant therapy of IV UH administered in the hospital (from 1995 to 1996 group, n = 64) or subcutaneous LMWH (enoxaparin) administered primarily at home (from 1997 to 1998 group, n = 65), followed by warfarin therapy.

RESULTS

No statistically significant differences were observed in the number of recurrent venous thromboembolic events (p = 0.36) or bleeding events (p = 1.0). Mean +/- SD cost per patient was 9,347 dollars +/- 8,469 in the enoxaparin group compared with 11,930 dollars +/- 10,892 in the UH group, a difference of - 2,583 dollars (95% bootstrap-adjusted asymmetrical confidence interval, - 6,147 dollars, + 650 dollars).

CONCLUSIONS

Retrospective replication of the Canadian study in a US routine (managed) care setting found similar clinical and economic outcomes. Treatment of acute proximal DVT with enoxaparin in a primarily outpatient setting can be accomplished safely and yields savings through avoidance or minimization of inpatient stays.