Integrating evidence on patient preferences in healthcare policy decisions: protocol of the patient-VIP study.

BACKGROUND: Despite a strong movement towards active patient involvement in healthcare policy decisions, systematic and explicit consideration of evidence of this research on patient preferences seems limited. Furthermore, little is known about the opinions of several stakeholders towards consideration of research evidence on patient preferences in healthcare policy decisions. This paper describes the protocol for an explorative study on the integration of research on patient preferences in healthcare policy decisions. The study questions: to what extent research evidence on patient preferences is considered in current procedures for healthcare policy decisions; opinions of stakeholders regarding the integration of this type of evidence in healthcare policy decisions; and what could be a decision framework for the integration of such research evidence in healthcare policy decisions. METHODS/DESIGN: The study is divided in three sub-studies, predominantly using qualitative methods. The first sub-study is a scoping review in five European countries to investigate whether and how results of research on patient preferences are considered in current procedures for coverage decisions and clinical practice guideline development. The second sub-study is a qualitative study to explore the opinions of stakeholders with regard to the possibilities for integrating evidence on patient preferences in the process of healthcare decision-making in the Netherlands. The third sub-study is the development of a decision framework for research on patient preferences. The framework will consist of: a process description regarding the place of evidence on patient preferences in the decision-making process; and a taxonomy describing different terminologies and conceptualisations of 'preferences' and an overview of existing methodologies for investigating preferences. The concept framework will be presented to and discussed with experts. DISCUSSION: This study will create awareness regarding the existence and potential value of research evidence on patient preferences for healthcare policy decision-making and provides insight in the methods for investigating patient preferences and the barriers and facilitators for integration of such research in healthcare policy decisions. Results of the study will be useful for researchers, clinical practice guideline developers, healthcare policy makers, and patient representatives.

Influence of spinline stress on release properties of a coaxial controlled release device based on EVA polymers.

PURPOSE: To investigate the influence of the extrusion parameters on the polymeric structure and release properties of polyethylene vinyl acetate (EVA) coaxial fibers, used for controlled release of steroids. METHODS: Coaxial fibers were prepared under various extrusion conditions. Both spinline stress and release properties were determined. The polymeric structure of the membrane was investigated with wide angle X-ray scattering (WAXS). RESULTS: Upon leaving the spinneret, the polymeric fiber exhibits a large die swell. As a consequence, it is necessary to apply a force to draw the fiber to its desired diameter. A larger drawing force is needed at lower extrusion temperature, at a smaller air gap, or at a higher spinning velocity. It was found that the release rate of a steroid from the coaxial fiber increases, when the fibers are prepared at a higher spinline stress. X-ray measurements reveal that at higher spinline stress, the crystalline volume fraction of the membrane decreases. As a result of a decreasing crystallinity, the permeability of the polymer increases. CONCLUSIONS: It is demonstrated that the extrusion parameters and spinline stress have a significant influence on the polymeric structure of the membrane and hence the release properties. Higher spinline stress results in a higher release rate.