Protocol of a clinical trial study involving educational intervention in patients treated with warfarin

Abstract

Background: Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide. Oral anticoagulation is an effective strategy for primary and secondary prevention of stroke in patients with AF. Warfarin is an oral anticoagulant widely prescribed and, despite its benefits, the achievement of the goals of drug therapy depends on patient involvement, among other factors. Educational interventions can contribute for effectiveness and safety of oral anticoagulation therapy. We sought to describe the protocol of a clinical trial designed to evaluate the effect of a patient-centered educational strategy focused on low-income patients with AF and poor anticoagulation control.

Methods: Patients ≥18 years with AF, on warfarin for at least 6 months and time in therapeutic range (TTR) <60% will be recruited at 2 anticoagulation clinics (ACs) in Brazil. Patients from 1 AC will be allocated to the intervention group and patients from the other AC will be allocated to the control group. Intervention group will attend educational sessions based on a patient-centered care approach, and the control group will receive usual care. The intervention will be based on Paulo Freire's theory and tailored according to practices involving health empowerment and techniques applied to individuals with limited socioeconomic status. The intervention is estimated to last 5 months. We will consider TTR as the primary outcome and knowledge and self-reported non-adherence to warfarin therapy as secondary outcomes. TTR values and non-adherence will be measured before intervention (T0) and at times immediately after (T1), and 3 (T2), 6 (T3), 9 (T4), and 12 (T5) months after intervention. Knowledge will be measured at times T0, T1 e T5. The calculated sample size indicated 85 patients in each group.

Discussion: The proposed study aims to investigate whether an innovative educational approach to deliver care to a low-income population on warfarin improves anticoagulation control. Once our hypothesis is confirmed, our findings are expected to help improving anticoagulation control, knowledge on warfarin therapy and adherence to drug therapy. Thus, we believe our results may contribute to improve oral anticoagulation effectiveness in a low-income population.

Trial registration: Registro Brasileiro de Ensaios Clínicos (ReBEC) RBR- 9cy6py and UTN: U1111-1217-0151 (March, 2019).

Figure 1

Intervention plan. AF = atrial fibrillation, TTR = time in therapeutic range.

Figure 2

Flow diagram. ACs = anticoagulation clinics, AF = atrial fibrillation, TTR = time in therapeutic range, INR = international normalized ratio.

Figure 3

Flowchart of the study phases. T1 = time 1, T2 = time 2, T3 = time 3, T4 = time 4, T5 = time 5, TTR = time in therapeutic range.