Resistant hypertension is a common health issue leading to high costs and suboptimal cardiovascular prevention. Non-adherence is one of the most common reasons, but proving non-adherence and, more importantly, improving adherence are challenging. We have developed a method to measure drug levels of the most commonly used antihypertensive drug in a dried blood spot (DBS) obtained by a finger prick.
RESEARCH QUESTION
Is providing patients with resistant hypertension with their drug levels (“biofeedback”) assessed by DBS-analysis combined with a behavioral change technique involving supported problem solving, an effective intervention to improve adherence and thereby to decrease the number of patients with assumed resistant hypertension?
HYPOTHESIS
Feedback on drug levels combined with supported problem-solving can improve adherence, and as a consequence blood pressure management.
STUDY DESIGN
A randomized controlled trial
STUDY POPULATION
Patients fulfilling the definition of resistant hypertension
INTERVENTION
Biofeedback combined with supported problem solving: firstly, barriers to adherence will be discussed and suggestions for modular interventions tailored to the underlying cause of non-adherence will be made. A psychologist and a sociologist are involved to develop the training and to train the involved doctors to perform the supported problem solving.
OUTCOME MEASURES
Primary: the number of patients fulfilling the definition of resistant hypertension after one year.
Secondary: the real number of patient with assumed resistant hypertension that is caused by non-adherence, cost effectiveness of the intervention, percentage of patients with resistant hypertension after 3& 6 months
SAMPLE SIZE/DATA-ANALYSIS
310 patients will be included to be able to identify a difference in RH between the intervention group and the control group of 10%, taking into account a decrease in the control group due to study effect. A multilevel analysis will be used to assess efficacy.