PhD defence L.E.J. (Laura) Peeters

Below is a brief summary about the dissertation:

Hypertension, also known as high blood pressure, is one of the main risk factors for cardiovascular diseases such as heart attacks and strokes, and it also increases the risk of kidney damage. The treatment of hypertension involves lifestyle adjustments, either alone or in combination with medication, including the use of blood pressure-lowering medication.

One of the main reasons for not reaching blood pressure goals in patients with hypertension is non-adherence to their prescribed antihypertensive therapy. Recognizing non-adherence by healthcare providers is challenging, which is why it is important to have a simple and objective method to determine non-adherence. Measuring drug levels in blood is one such objective method.

To increase the clinical applicability of measuring drug levels for use inside and outside the hospital, we have developed a dried blood spot (DBS) method. With DBS, a drop of blood is obtained through a finger prick and applied to a card. Additionally, in collaboration with a psychologist and a sociologist, a communication tool has been designed to support discussions about non-adherence. The DBS method and communication tool were applied in a randomized controlled multicenter study where we aimed to improve non-adherence and thereby blood pressure in patients with resistant hypertension. In this study, we found that blood pressure significantly improved in both the control and intervention arm due to participation in the research. In the intervention arm adherence also improved significantly. 

Finally, this thesis demonstrates the possibilities, beyond adherence, of measuring antihypertensive drug levels in blood for optimizing blood pressure-lowering therapy.