Pooled analysis shows LAAC is cheaper than drug therapy for AF

Vivek Reddy

A pooled analysis of five-year data from the PROTECT AF and PREVAIL trials has shown left atrial appendage closure (LAAC) to be cost‐effective, and to save costs in comparison to warfarin or non-vitamin K antagonist oral anticoagulant (NOAC) therapy.

Published in the Journal of the American Heart Association, the study by Vivek Reddy (Mount Sinai, New York, USA) et al also concludes: “LAAC with the Watchman device [Boston Scientific] is an economically viable stroke risk reduction strategy for patients with atrial fibrillation seeking an alternative to lifelong anticoagulation.”

The authors say that previously published US economic analyses used interim data from the individual trials, and that theirs is the first complete, five-year pooled analysis of PROTECT AF (Watchman Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation) and PREVAIL (Prospective Randomized Evaluation of the Watchman LAA Closure Device in Patients With Atrial Fibrillation Versus Long‐Term Warfarin).

“This comprehensive assessment uses the most complete body of clinical evidence for LAAC in an attempt to more definitively evaluate the therapy’s economic value and provide guidance for future analyses,” they say.

The investigators evaluated the cost‐effectiveness of three treatment strategies—LAAC with the Watchman device, NOACs as a class, and adjusted‐dose warfarin. They constructed a Markov model from the perspective of the Centers for Medicare and Medicaid Services with a lifetime horizon (defined as 20 years) and three‐month cycle length. Within each cycle, patients could experience clinical events leading to death, disability, and/or therapy discontinuation, and incur associated costs and quality‐of‐life (QoL) adjustments. LAAC clinical event rates and stroke outcomes from five‐year data of the PROTECT AF and PREVAIL trials were pooled, and warfarin and NOAC inputs derived from published meta‐analyses. The model was populated with a cohort of 10,000 patients, aged 70 years, who were at moderate stroke and bleeding risk, and sensitivity analyses were performed.

Cost‐effectiveness was evaluated using the willingness-to-pay threshold of US$50,000 per quality‐adjusted life‐year (QALY), the value that is commonly accepted in the USA; it was reported as the incremental cost‐effectiveness ratio (ICER). Cost‐effectiveness was assessed annually to determine the time point at which the different treatment options achieved accepted levels of cost‐effectiveness.

Reddy et al found that LAAC was cost‐effective relative to warfarin by year seven ($US48,674/quality‐adjusted life‐year [QALY]) and dominant (more effective and less costly) by year 10. LAAC became cost‐effective and dominant compared with NOACs by year five. Over a lifetime, LAAC provided 0.6 more QALYs than warfarin and 0.29 more than NOACs. In sensitivity analyses, LAAC was cost‐effective relative to warfarin and NOACs in 98% and 95% of simulations, respectively.

Among the limitations of the analysis listed by the authors were that clinical inputs were derived from different sources, including pivotal trials and meta-analyses and that indirect comparison were necessary as there is no randomised controlled trial that directly compares LAAC with NOACs. In addition, the studies had different lengths of follow-up and data were extrapolated to 20 years. However, they point out: “Five years of follow-up in the PROTECT AF and PREVAIL trials is substantial by stroke prevention RCT standards.” They also suggest that further research is needed to understand long-term adherence to OAC therapy.

Reddy et al conclude: “Despite the increased risk of ischaemic stroke observed in the PREVAIL trial, left atrial appendage closure is cost‐effective and cost saving relative to nonwarfarin oral anticoagulants and warfarin when the full body of randomised controlled trial data is taken into consideration. LAAC with the Watchman device is an economically viable stroke risk reduction strategy for patients with AF seeking an alternative to lifelong anticoagulation.”

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