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)

Abstract

Background: Atrial 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 findings: We 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.

Conclusions: The 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 registration: ClinicalTrials.gov NCT02635685.

Fig 1. The clinical decision support tool for improving adherence to guidelines on anticoagulant therapy.

CDS, clinical decision support tool; NOAC, non–vitamin K oral anticoagulant; VKA, vitamin K antagonist; TIA, transient ischemic attack.

Fig 2. The CONSORT flow diagram of trial participants.

*Patients were transferred to other primary care clinics and were included in the final intention to treat analysis. AF, atrial fibrillation; CDS, clinical decision support tool.

Fig 3. Proportion of eligible patients prescribed anticoagulant therapy after 12 months in control and CDS groups.

Rate of adherence to guidelines presented as percentage on the y-axis, with the different study groups over time on the x-axis. Data are presented as mean ± SD. *p = 0.013. CDS, clinical decision support tool.

Fig 4. Flowchart of the specified reasons for not initiating anticoagulant therapy.

Fig 5. Number of times the clinical decision support alert was shown for the first time in unique individuals throughout the study period.