Purpose The aims of this study were to investigate (1) the extent to which response shift occurs among patients with coronary artery disease (CAD) after coronary revascularization, (2) whether the... Show morePurpose The aims of this study were to investigate (1) the extent to which response shift occurs among patients with coronary artery disease (CAD) after coronary revascularization, (2) whether the assessment of changes in health-related quality of life (HRQoL), controlled for response shift, yield more valid estimates of changes in HRQoL, as indicated by stronger associations with criterion measures of change, than without controlling for response shift, and (3) if occurrences of response shift are related to patient characteristics. Methods Patients with CAD completed the SF-36 and the Seattle Angina Questionnaire (SAQ7) at baseline and 3 months after coronary revascularization. Sociodemographic, clinical and psychosocial variables were measured with the patient version of the New York Heart Association-class, Subjective Significance Questionnaire, Reconstruction of Life Events Questionnaire (RE-LIFE), and HEXACO personality inventory. Oort's Structural Equation Modeling (SEM) approach was used to investigate response shift. Results 191 patient completed questionnaires at baseline and at 3 months after treatment. The SF-36 showed recalibration and reprioritization response shift and the SAQ7 reconceptualization response shift. Controlling for these response shift effects did not result in more valid estimates of change. One significant association was found between reprioritization response shift and complete integration of having CAD into their life story, as indicated by the RE-LIFE. Conclusion Results indicate response shift in HRQoL following coronary revascularization. While we did not find an impact of response shift on the estimates of change, the SEM approach provides a more comprehensive insight into the different types of change in HRQoL following coronary revascularization. Show less
Blankers, M.; Buisman, R.; Hopman, P.; Van Gool, R.; Van Laar, M. 2016
The clinical heterogeneity of Parkinson__s disease (PD) patients may reflect the existence of subtypes of the disease. PD subtypes have often been defined by a classification according to... Show moreThe clinical heterogeneity of Parkinson__s disease (PD) patients may reflect the existence of subtypes of the disease. PD subtypes have often been defined by a classification according to researcher-specified criteria, such as age-at-onset or predominant clinical motor features. The general objective of this thesis was to identify and characterize clinical subtypes in PD by a data-driven approach, based on a comprehensive assessment of all relevant PD domains. In order to obtain insight in the associations and coherence of impairments that are involved in the disease, we evaluated the contributions of impairment and disability domains to health-related quality of life in patients with PD. Subsequently, the data of the PROPARK cohort was used to study coherency patterns within the motor domain and in the spectrum of motor and nonmotor domains. In our study on subtypes, first, we systematically evaluated the result s of earlier studies that performed cluster analysis to identify subtypes in PD, after which we applied cluster analysis on data of the PROPARK cohort in order to identify subtypes of the disease. Show less
