P3815Cost and burden of poor control of the level of anticoagulation in patients with non-valvular atrial fibrillation treated with vitamin K antagonist in the Spanish National Health Service
Authors: Burgos-Pol R , Barrios V , Cinza-Sanjurjo S , Gavin O , Egocheaga I , Soto J , Polanco C , Suarez J , Casado M A 
Published: October 2019

Abstract

Introduction
Poorly controlled non-valvular atrial fibrillation (NVAF) patients treated with vitamin K antagonists (VKA) experience higher rates of clinical events compared to well controlled patients. In Spain a high percentage of NVAF patients present an inadequate control of anticoagulation therapy, whose economic impact has not been reported yet.

Purpose
To estimate the impact on resource consumption, clinical events and mortality of poorly controlled NVAF patients≥65 years treated with VKA in Spain.

Methods
A cost-consequence analytic model was developed to estimate differences on clinical events and cost between poorly controlled (TTR<65%) and well controlled (TTR≥65%) NVAF patients treated with VKA over 1 year. A hypothetical cohort of NVAF patients was estimated by using local epidemiological studies. Anticoagulation control rates, as measured by Rosendaal method, were retrieved from a literature review of Spanish real-world studies.
Clinical event rates (ischemic stroke-IS-, hemorrhagic stroke-HS-, major bleeding-MB-, systemic embolism-SE- and death for any cause) were derived from a post-hoc analysis of SPORTIF III/V trials. A sensitivity analysis (SA) was performed by using event rates from a prospective single-center study carried out in Spain.
Societal and National Health Service (NHS) perspectives were considered. Total annual costs (€ 2018) included clinical event direct, non-direct healthcare cost and indirect-costs. Potential life years lost (PLYL) were calculated to report impact on mortality. An expert panel composed by a cardiologist, a haematologist and general practitioners validated the model inputs.

Results
The target population comprised 594,855 NVAF patients treated with VKA (mean age 73.2 years, 49.4% women, 74.1% CHADS≥2). Poorly controlled anticoagulated patients accounted for 48.3% of the cohort. The inadequate control of anticoagulation was associated with a higher incidence of clinical events compared to well controlled patients within a year (additional 2,143 IS, 390 HS, 201 SE, 6,190 MB and 6,856 deaths). From NHS perspective, the incremental total annual costs associated to poorly controlled patients were €46,685,756.60 (€173.96/patient-year). When considering the societal perspective, the incremental total annual costs of inadequate anticoagulation control reached €97,787,872.59 (€367.51/patient-year). Mortality due to poorly anticoagulation control implied 80,830.65 PLYL (0.136 PLYL/patient-year). The SA confirmed the base case results.

Conclusions
In the Spanish NHS, around 50% of NVAF patients ≥65 years treated with VKA present an inadequate control of the anticoagulation therapy (287,089 patients), which is associated with the increase of clinical events, mortality and costs (up to €100 million). The results of this study highlight a call to action to increase the awareness of the consequences of a poor anticoagulation control and emphasize the need for a better clinical of patients receiving anticoagulation.

Acknowledgement/Funding
BMS and PFIZER contributed to finance the no conditioned to the results of this work.