Cost-effectiveness of additional catheter-directed thrombolysis for deep vein thrombosis

Abstract

Background: Additional treatment with catheter-directed thrombolysis (CDT) has recently been shown to reduce post-thrombotic syndrome (PTS).

Objectives: To estimate the cost effectiveness of additional CDT compared with standard treatment alone.

Methods: Using a Markov decision model, we compared the two treatment strategies in patients with a high proximal deep vein thrombosis (DVT) and a low risk of bleeding. The model captured the development of PTS, recurrent venous thromboembolism and treatment-related adverse events within a lifetime horizon and the perspective of a third-party payer. Uncertainty was assessed with one-way and probabilistic sensitivity analyzes. Model inputs from the CaVenT study included PTS development, major bleeding from CDT and utilities for post DVT states including PTS. The remaining clinical inputs were obtained from the literature. Costs obtained from the CaVenT study, hospital accounts and the literature are expressed in US dollars ($); effects in quality adjusted life years (QALY).

Results: In base case analyzes, additional CDT accumulated 32.31 QALYs compared with 31.68 QALYs after standard treatment alone. Direct medical costs were $64,709 for additional CDT and $51,866 for standard treatment. The incremental cost-effectiveness ratio (ICER) was $20,429/QALY gained. One-way sensitivity analysis showed model sensitivity to the clinical efficacy of both strategies, but the ICER remained < $55,000/QALY over the full range of all parameters. The probability that CDT is cost effective was 82% at a willingness to pay threshold of $50,000/QALY gained.

Conclusions: Additional CDT is likely to be a cost-effective alternative to the standard treatment for patients with a high proximal DVT and a low risk of bleeding.

Keywords: anticoagulation; cost-effectiveness analysis; decision model; post-thrombotic syndrome; thrombolytic therapy; venous thrombosis.

Fig. 1

Model states, events and transitions. The boxes represent the different health states of the model. All patients start in an index deep vein thrombosis (DVT) state and, unless an adverse event occurs, transition to a post DVT state in which they remain until an adverse event occurs. The events that can lead to a state transition are represented by the different arrows.

Fig. 2

One-way sensitivity analyzes on variables that most influenced the incremental cost effectiveness of additional catheter-directed thrombolysis (CDT) compared with standard treatment alone. Bars indicate the range of incremental cost per additional QALY of additional CDT compared with standard treatment alone as determined in one-way sensitivity analyzes over plausible parameter ranges. Upper and lower value limits evaluated are indicated next to its respective bar. One-way sensitivity analysis was done for all model parameters, and the cost-effectiveness varied the most with the variables shown. The solid vertical axis represents the incremental cost-effectiveness ratio for the base case. The dotted line represents a willingness-to-pay threshold of $50 000 per QALY. All costs are per 6 months unless otherwise stated.

Fig. 3

Two-way sensitivity analysis of severe catheter-directed thrombolysis(CDT) complication risks. Two-way sensitivity analysis of the risks of severe CDT complications comparing the net benefits (highest effectiveness and lowest costs) of the CDT strategy with the standard treatment strategy at a willingness-to-pay (WTP) threshold of $50 000/QALY gained. At high risks the standard treatment strategy yields the highest net benefits. At a lower WTP threshold ($20 000) the standard treatment strategy yields the highest net benefits also at low risks, whereas at a high WTP threshold ($100 000) the CDT strategy yields the highest net benefits at most risk values.

Fig. 4

Cost-effectiveness acceptability curves for additional catheter-directed thrombolysis strategy and standard treatment strategy. The graph represents the probability that each treatment strategy is cost effective for a given willingness-to-pay threshold per QALY gained. The curves are based on 10 000 Monte Carlo simulations of the model with simultaneous draws of parameters from their respective probability distributions for each input.