Efficacy of a Health Belief Model Based Intervention for Anticoagulation Adherence in Patients With Atrial Fibrillation: A Randomized Controlled Trial

BACKGROUND: Inconsistent anticoagulation therapy in AF patients is associated with a higher risk of stroke and abnormal bleeding. However, control of oral anticoagulation therapy in AF patients has been frequently reported as inadequate. Few theoretical based interventions have been tested for enhancing medication adherence in this population. Previous studies showed that the health belief model may offer some advantage over other behavior change theories for enhancing medication adherence in adult with chronic conditions.

PURPOSE: The purpose of the study is to investigate the efficacy of a health belief model based self-management of oral anticoagulant therapy intervention on the outcome of medication adherence and the mediators of knowledge, professional support, health belief, and self-efficacy in patients treated with oral anticoagulants for atrial fibrillation.

METHODS: The study is a randomized clinical trial with repeated measurements. A convenient sample of 72 adults who were treated with anticoagulants for atrial fibrillation was recruited from two teaching hospitals in northern Taiwan. Participants were randomly assigned 1:1 to either the control group (n = 36) or the intervention group (n = 36) after completion of baseline questionnaires. Allocation was balanced by site by using a minimization method. The health belief model based self-management intervention comprised two main components: a 60-minute individual face to face instruction and six follow-up telephone calls. Participants in the control group received regular medication education, 10-minute individual instruction for health knowledge and six follow-up telephone calls for concerning health. Data were collected at baseline, third month, and sixth month in both groups, by using self-administered questionnaires. The investigator administered the study questionnaire after obtaining informed consent from each subject. The data collection took place at the waiting areas outside the outpatient clinics during the patients' visits to the clinics. For subjects who were unable to read the questionnaire due to vision or other problems, the investigator read each question to help them complete the questionnaire. The instruments include the Atrial Fibrillation Knowledge Scale, Satisfaction Scale about Service and Warfarin Treatment, Belief About Anticoagulation Survey, and Self-Efficacy for Appropriate Medication Use Scale.

DATA ANALYSIS: Data were analyzed using the Statistical Package for Social Sciences 20.0 (SPSS, Inc., Chicago, IL, USA). Descriptive analyses were used to describe study variables. Independent t-tests and one-way analysis of variance (ANOVA) were performed to analyze the baseline equivalent between study groups. The generalized estimating equations were used to analyze the efficacy of the intervention for enhancing knowledge, knowledge, perceived benefits, perceived barriers, self-efficacy, and adherence to anticoagulant therapies in patients treated with oral anticoagulants for atrial fibrillation.