Von Willebrand Factor Multimer Densitometric Analysis:Validation of the Clinical Accuracy and Clinical Implications in Von Willebrand Disease

Von Willebrand factor (VWF) multimer analysis is important in the classification of von Willebrand disease (VWD). Current visual VWF multimer analysis is time consuming and inaccurate in detecting subtle changes in multimer patterns. Although VWF multimer densitometric analysis may be useful, the accuracy needs further investigation before it can be widely applied. In this study we aimed to validate VWF multimer densitometric analysis in a large cohort of VWD patients and to identify patient characteristics associated with densitometric outcomes. Patients were included from the Willebrand in the Netherlands (WiN) study, in which a bleeding score (BS) was obtained, and blood was drawn. For multimer analysis, citrated blood was separated on an agarose gel and visualized by Western blotting. IMAGEJ was used to generate densitometric images and medium-large VWF multimer index was calculated. We included 560 VWD patients: 328 type 1, 211 type 2, and 21 type 3 patients. Medium-large VWF multimer index performed excellent in distinguishing visually classified normal VWF multimers from reduced high-molecular-weight (HMW) multimers (area under the curve [AUC]: 0.96 [0.94-0.98], P < 0.001), normal multimers from absence of HMW multimers (AUC 1.00 [1.00-1.00], P < 0.001), and type 2A and 2B from type 2M and 2N (AUC: 0.96 [0.94-0.99], P < 0.001). Additionally, higher medium-large VWF multimer index was associated with lower BS in type 1 VWD: beta = -7.6 (-13.0 to -2.1), P = 0.007, adjusted for confounders. Densitometric analysis of VWF multimers had an excellent accuracy compared with visual multimer analysis and may contribute to a better understanding of the clinical features such as the bleeding phenotype of VWD patients

A pilot qualitative study to explore stakeholder opinions regarding prescribing quality indicators

Background: Information on prescribing quality of diabetes care is required by health care providers, insurance companies, policy makers, and the public. Knowledge regarding the opinions and preferences of all involved parties regarding prescribing quality information is important for effective use of prescribing quality indicators. Methods: Between June and December 2009 we conducted semi structured interviews with 16 key-informants representing eight different organizations in the Netherlands involved in healthcare quality measurement and improvement. The interview guide included topics on participants' opinions and preferences regarding existing types of prescribing quality indicators in relation to their aim of using quality information. Content analysis methods were used to process the resulting transcripts following the framework of predetermined themes. Results: Findings from this qualitative study of stakeholder preferences showed that indicators focusing on undertreatment are found important by all participants. Furthermore, health care providers and policy makers valued prescribing safety indicators, insurance companies prioritized indicators focusing on prescribing costs, and patients' organization representatives valued indicators focusing on interpersonal side of prescribing. Representatives of all stakeholders preferred positive formulation of the indicators to motivate health care providers to participate in health improvement programs. A composite score was found to be most useful by all participants as a starting point of prescribing quality assessment. Lack of information on reasons for deviating from guidelines recommendations appeared to be the most important barrier for using prescribing quality indicators. According to the health care providers, there are many legitimate reasons for not prescribing the recommended treatment and these reasons are not always taken into account by external evaluators. The latter may cause mistrust of health care providers towards external stakeholders and limit the use of PQI in external quality improvement programs. Conclusion: Prescribing quality indicators are considered to be an important tool for assessing quality of provided diabetes care by all participants, although the preferences for specific types of indicators may differ by stakeholder depending on their user aim. Introduction of information systems to register the reasons for deviating from the recommended drug treatment may contribute to a more widespread use of PQI for assessment of provided health care quality to diabetic patents. This study identified the potential preferences regarding quality indicators for diabetes care, and this could be used for development of questionnaires to conduct a survey among a larger group of participants