Research Article: A clinical decision support tool for improving adherence to guidelines on anticoagulant therapy in patients with atrial fibrillation at risk of stroke: A cluster-randomized trial in a Swedish primary care setting (the CDS-AF study)

Date Published: March 13, 2018

Publisher: Public Library of Science

Author(s): Lars O. Karlsson, Staffan Nilsson, Magnus Bång, Lennart Nilsson, Emmanouil Charitakis, Magnus Janzon, Steven R. Steinhubl

Abstract: BackgroundAtrial fibrillation (AF) is associated with substantial morbidity, in particular stroke. Despite good evidence for the reduction of stroke risk with anticoagulant therapy, there remains significant undertreatment. The main aim of the current study was to investigate whether a clinical decision support tool (CDS) for stroke prevention integrated in the electronic health record could improve adherence to guidelines for stroke prevention in patients with AF.Methods and findingsWe conducted a cluster-randomized trial where all 43 primary care clinics in the county of Östergötland, Sweden (population 444,347), were randomized to be part of the CDS intervention or to serve as controls. The CDS produced an alert for physicians responsible for patients with AF and at increased risk for thromboembolism (according to the CHA2DS2-VASc algorithm) without anticoagulant therapy. The primary endpoint was adherence to guidelines after 1 year. After randomization, there were 22 and 21 primary care clinics in the CDS and control groups, respectively. There were no significant differences in baseline adherence to guidelines regarding anticoagulant therapy between the 2 groups (CDS group 70.3% [5,186/7,370; 95% CI 62.9%–77.7%], control group 70.0% [4,187/6,009; 95% CI 60.4%–79.6%], p = 0.83). After 12 months, analysis with linear regression with adjustment for primary care clinic size and adherence to guidelines at baseline revealed a significant increase in guideline adherence in the CDS (73.0%, 95% CI 64.6%–81.4%) versus the control group (71.2%, 95% CI 60.8%–81.6%, p = 0.013, with a treatment effect estimate of 0.016 [95% CI 0.003–0.028]; number of patients with AF included in the final analysis 8,292 and 6,508 in the CDS and control group, respectively). Over the study period, there was no difference in the incidence of stroke, transient ischemic attack, or systemic thromboembolism in the CDS group versus the control group (49 [95% CI 43–55] per 1,000 patients with AF in the CDS group compared to 47 [95% CI 39–55] per 1,000 patients with AF in the control group, p = 0.64). Regarding safety, the CDS group had a lower incidence of significant bleeding, with events in 12 (95% CI 9–15) per 1,000 patients with AF compared to 16 (95% CI 12–20) per 1,000 patients with AF in the control group (p = 0.04). Limitations of the study design include that the analysis was carried out in a catchment area with a high baseline adherence rate, and issues regarding reproducibility to other regions.ConclusionsThe present study demonstrates that a CDS can increase guideline adherence for anticoagulant therapy in patients with AF. Even though the observed difference was small, this is the first randomized study to our knowledge indicating beneficial effects with a CDS in patients with AF.Trial NCT02635685

Partial Text: Atrial fibrillation (AF) has a prevalence of more than 3% in developed countries [1] and is estimated to affect more than 33 million people worldwide [2]. The condition carries an increased risk of thromboembolism, in particular stroke. The Global Burden of Disease project estimated the incidence of ischemic stroke at more than 6 million cases worldwide in 2013 [3]. Of these, approximately 20% are attributable to AF [3,4]. Moreover, stroke in patients with AF more often leads to permanent disability and death than stroke from other causes [5].

The technical aspects of the CDS and the study design, with additional secondary outcomes, have been published elsewhere [21]. What follows is an overview of the CDS and the overall study design.

All 43 primary care clinics in the county of Östergötland eligible for inclusion consented to participate in the study. Of the 14,134 patients with AF at baseline, 13,379 had an indication for anticoagulant therapy according to current guidelines. One primary care clinic in the control group was lost to follow-up due to closedown. The 287 patients with AF listed at that clinic were allocated to other clinics and were included in the final intention to treat analysis. In the final analysis, 42 primary care clinics with a total of 14,800 patients with AF were included (Fig 2). During the study period, 1,857 patients received a new diagnosis of AF and were included in the final analysis.

The present study demonstrates that a newly developed clinical decision support system yields a small increase in adherence to guidelines regarding stroke prevention in patients with AF. During the study period of 1 year, the intervention did not translate into a clinically significant reduction in stroke, TIA, and systemic thromboembolism. This study serves as a proof of concept that an easily available technique could increase preventive measures in healthcare.



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