Cost-effectiveness of alternative anticoagulation strategies for postoperative management of total knee arthroplasty patients.

OBJECTIVE: Evaluate the cost-effectiveness of prolonged (35-day) and standard (14-day) duration anticoagulation therapy following total knee arthroplasty (TKA).

METHODS: Using Markov modeling, we assessed clinical and economic outcomes of 14-day and 35-day anticoagulation therapy following TKA with rivaroxaban, low molecular weight heparin (LMWH), fondaparinux, warfarin, and aspirin. Incidence of complications of TKA and anticoagulation - DVT, PE, prosthetic joint infection (PJI), and bleeding - were derived from published literature. Daily costs ranged from $1 (aspirin) to $43 (fondaparinux). Primary outcomes included quality-adjusted life years (QALYs), direct medical costs, and incremental cost-effectiveness ratios (ICERs) at one-year post-TKA. The preferred regimen was the regimen with highest QALYs maintaining an ICER below the willingness-to-pay threshold ($100,000/QALY). We conducted probabilistic sensitivity analyses, varying complication incidence and anticoagulation efficacy, to evaluate the impact of parameter uncertainty on model results.

RESULTS: Aspirin resulted in the highest cumulative incidence of DVT and PE, while prolonged fondaparinux led to the largest reduction in DVT incidence (15% reduction compared to no prophylaxis). Despite differential bleeding rates (ranging from 3% to 6%), all strategies had similar incidence of PJI (1-2%). Prolonged rivaroxaban was the least costly strategy ($3,300 one year post-TKA) and the preferred regimen in the base case. In sensitivity analyses, prolonged rivaroxaban and warfarin had similar likelihoods of being cost-effective.

CONCLUSIONS: Extending post-operative anticoagulation to 35 days increases QALYs compared to standard 14-day prophylaxis. Prolonged rivaroxaban and prolonged warfarin are most likely to be cost-effective post-TKA; the costs of fondaparinux and LMWH precluded their being preferred strategies. This article is protected by copyright. All rights reserved.