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.