Postthrombotic syndrome

Economic burden of long-term complications of deep vein thrombosis after total hip replacement surgery in the United States

BACKGROUND

Estimates of the cost of long-term complications of a primary deep vein thrombosis (DVT), including the post-thrombotic syndrome (PTS) and recurrent venous thromboembolism (VTE), may be relevant for resource allocation decisions.

OBJECTIVE

The objective of this study was to provide US cost estimates of the long-term complications of a primary DVT, which occurs in approximately 5% to 20% (with adequate thromboprophylaxis) and 50% (in the absence of thromboprophylaxis) of total hip replacement surgeries (THRS).

METHODS

A literature-based model was used to project the excess long-term complication costs of DVT following THRS. The model simulated the natural history of DVT complications using published estimates of the incidence and prognosis of PTS and recurrent VTE. Each complication was assigned a cost obtained by multiplying the amount of resources used in its management by the unit price of these resources.

RESULTS

The annual per-patient cost of each complication was as follows: mild-to-moderate PTS, 839 dollars in the first year and 341 dollars in subsequent years; severe PTS, 3817 dollars in the first year and 1677 dollars in subsequent years; DVT, 3798 dollars; and pulmonary embolism, 6604 dollars. The average discounted lifetime cost of DVT complications was estimated to be 3069 dollars (95% interval 2091 dollars-4279 dollars).

CONCLUSIONS

The long-term complications of a primary DVT represent a significant economic burden. Preventing a DVT could arguably lead to substantial savings in long-term DVT complications.

Results of an economic model to assess the cost-effectiveness of enoxaparin, a low-molecular-weight heparin, versus warfarin for the prophylaxis of deep vein thrombosis and associated long-term complications in total hip replacement surgery in the United States

BACKGROUND

Premature death due to pulmonary embolism is a short-term complication of deep vein thrombosis (DVT). The long-term clinical course after DVT can be further complicated by excess mortality, recurrent venous thromboembolism (VTE), and the post-thrombotic syndrome (PTS), which may produce sizable long-term economic burdens.

OBJECTIVE

The goal of this study was to determine the cost-effectiveness of the low-molecular-weight heparin (LMWH) enoxaparin versus warfarin for the universal prophylaxis of DVT and associated long-term complications in US patients undergoing total hip replacement surgery (THRS).

METHODS

A model was constructed to assess the long-term cost-effectiveness of the 2 treatments. Patients undergoing THRS were exposed to a short-term risk of developing a DVT. Patients surviving a DVT were exposed to increased risk of long-term complications of DVT, including PTS, recurrent VTE, and increased mortality. Published literature, augmented by expert opinion, served as input for the model's resource use and costs for DVT prophylaxis, clinical diagnosis, and treatment of DVT, VTE, and PTS.

RESULTS

When the analysis included only the short-term consequences of DVT, therapy with enoxaparin resulted in a net cost of $133 per patient and a net increase of 0.04 quality-adjusted life-years (QALYs) per patient. Thromboprophylaxis with enoxaparin versus warfarin resulted in $3733 per QALY saved. In contrast, when the long-term consequences of DVT were included, enoxaparin resulted in net lifetime savings of $89 per patient and net QALY benefits of 0.16 per patient.

CONCLUSIONS

To the best of our knowledge, this is the first US economic analysis comparing DVT prophylaxis with the LMWH enoxaparin versus warfarin that included the long-term complications of DVT. Our model suggests that use of enoxaparin in patients undergoing THRS reduces the economic burden associated with these long-term complications.