In this thesis, we aimed to develop and validate a patient and a physician questionnaire to measure the shared decision making (SDM) process in oncology. We identified SDM measurement challenges:... Show moreIn this thesis, we aimed to develop and validate a patient and a physician questionnaire to measure the shared decision making (SDM) process in oncology. We identified SDM measurement challenges: there is limited evidence on measurement properties, patients’ role is not assessed while it is present in SDM models, patients and healthcare professionals have been involved only to a limited extent in the development of SDM measurement instruments, and a reflective measurement model is often assumed, while a formative might be more appropriate. The aim of this thesis was therefore to develop and validate questionnaires to assess the SDM process in oncology from both the patient and the physician viewpoints. We chose the oncology setting because it is a setting in which patients often face preference-sensitive decisions, and in which most patients prefer an active or collaborative role in treatment decision making. To inform the development and validation process of our questionnaires, we used the original Consensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist and we wrote two reviews: one on existing SDM measurement instruments and one on existing SDM models. The iSHARE questionnaires shows adequate measurement properties Show less
Objectives: We have developed two Dutch questionnaires to assess the shared decision-making (SDM) process in oncology; the iSHAREpatient and iSHAREphysician. In this study, we aimed to determine:... Show moreObjectives: We have developed two Dutch questionnaires to assess the shared decision-making (SDM) process in oncology; the iSHAREpatient and iSHAREphysician. In this study, we aimed to determine: scores, construct validity, test-retest agreement (iSHAREpatient), and inter-rater (iSHAREpatient-iSHAREphysician) agreement. Methods: Physicians from seven Dutch hospitals recruited cancer patients, and completed the iSHAREphysician and SDM-Questionnaire-physician version. Their patients completed the: iSHAREpatient, nine-item SDM-Questionnaire, Decisional Conflict Scale, Combined Outcome Measure for Risk communication And treatment Decision-making Effectiveness, and five-item Perceived Efficacy in Patient-Physician Interactions. We formulated, respectively, one (iSHAREphysician) and 10 (iSHAREpatient) a priori hypotheses regarding correlations between the iSHARE questionnaires and questionnaires assessing related constructs. To assess test-retest agreement patients completed the iSHAREpatient again 1-2 weeks later. Results: In total, 151 treatment decision-making processes with unique patients were rated. Dimension and total iSHARE scores were high both in patients and physicians. The hypothesis on the iSHAREphysician and 9/10 hypotheses on the iSHAREpatient were confirmed. Test-retest and inter-rater agreement were >.60 for most items. Conclusions: The iSHARE questionnaires show high scores, have good construct validity, substantial test-retest agreement, and moderate inter-rater agreement. Practice implications: Results from the iSHARE questionnaires can inform both physician- and patient-directed efforts to improve SDM in clinical practice. Show less
